Replaced IpPrefix and IpAddress in the following methods
and cleanup related code:

 - Host.ipAddresses()
 - DefaultHost.ipAddresses()
 - HostDescription.ipAddress()
 - DefaultHostDescription.ipAddress()
 - HostService.getHostsByIp()
 - HostManager.getHostsByIp()
 - HostStore.getHosts()
 - GossipHostStore.getHosts()
 - SimpleHostStore.getHosts()
 - ProxyArpService.known()
 - ProxyArpManager.known()

As a result of the above cleanup, the "hosts" CLI command outputs
the IP addresses as "1.2.3.4" instead of "1.2.3.4/32".

Also, the following REST calls might be affected as well with
the above format replacement:
  - REST POST: config/topology
  - REST GET: topology/graph
diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/Router.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/Router.java
index 0907cd6..4e3415b 100644
--- a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/Router.java
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/Router.java
@@ -520,8 +520,7 @@
 
         // See if we know the MAC address of the next hop
         MacAddress nextHopMacAddress = null;
-        Set<Host> hosts = hostService.getHostsByIp(
-                routeEntry.nextHop().toPrefix());
+        Set<Host> hosts = hostService.getHostsByIp(routeEntry.nextHop());
         if (!hosts.isEmpty()) {
             // TODO how to handle if multiple hosts are returned?
             nextHopMacAddress = hosts.iterator().next().mac();
@@ -773,8 +772,8 @@
             if (event.type() == HostEvent.Type.HOST_ADDED ||
                     event.type() == HostEvent.Type.HOST_UPDATED) {
                 Host host = event.subject();
-                for (IpPrefix ip : host.ipAddresses()) {
-                    updateMac(ip.toIpAddress(), host.mac());
+                for (IpAddress ip : host.ipAddresses()) {
+                    updateMac(ip, host.mac());
                 }
             }
         }
diff --git a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
index 13547ae..7bc9473 100644
--- a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
+++ b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
@@ -197,27 +197,27 @@
         hostService.addListener(anyObject(HostListener.class));
         expectLastCall().anyTimes();
 
-        IpPrefix host1Address = IpPrefix.valueOf("192.168.10.1/32");
+        IpAddress host1Address = IpAddress.valueOf("192.168.10.1");
         Host host1 = new DefaultHost(ProviderId.NONE, HostId.NONE,
                 MacAddress.valueOf("00:00:00:00:00:01"), VlanId.NONE,
                 new HostLocation(SW1_ETH1, 1),
-                        Sets.newHashSet(host1Address));
+                Sets.newHashSet(host1Address));
 
         expect(hostService.getHostsByIp(host1Address))
                 .andReturn(Sets.newHashSet(host1)).anyTimes();
-        hostService.startMonitoringIp(host1Address.toIpAddress());
+        hostService.startMonitoringIp(host1Address);
         expectLastCall().anyTimes();
 
 
-        IpPrefix host2Address = IpPrefix.valueOf("192.168.20.1/32");
+        IpAddress host2Address = IpAddress.valueOf("192.168.20.1");
         Host host2 = new DefaultHost(ProviderId.NONE, HostId.NONE,
                 MacAddress.valueOf("00:00:00:00:00:02"), VlanId.NONE,
                 new HostLocation(SW2_ETH1, 1),
-                        Sets.newHashSet(host2Address));
+                Sets.newHashSet(host2Address));
 
         expect(hostService.getHostsByIp(host2Address))
                 .andReturn(Sets.newHashSet(host2)).anyTimes();
-        hostService.startMonitoringIp(host2Address.toIpAddress());
+        hostService.startMonitoringIp(host2Address);
         expectLastCall().anyTimes();
 
 
diff --git a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTestWithAsyncArp.java b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTestWithAsyncArp.java
index c2e2019..d1c8b2a 100644
--- a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTestWithAsyncArp.java
+++ b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTestWithAsyncArp.java
@@ -184,7 +184,7 @@
 
         // Set up test expectation
         reset(hostService);
-        expect(hostService.getHostsByIp(anyObject(IpPrefix.class))).andReturn(
+        expect(hostService.getHostsByIp(anyObject(IpAddress.class))).andReturn(
                 new HashSet<Host>()).anyTimes();
         hostService.startMonitoringIp(IpAddress.valueOf("192.168.10.1"));
         replay(hostService);
@@ -203,7 +203,7 @@
                 new HostLocation(
                         SW1_ETH1.deviceId(),
                         SW1_ETH1.port(), 1),
-                        Sets.newHashSet(IpPrefix.valueOf("192.168.10.1/32")));
+                        Sets.newHashSet(IpAddress.valueOf("192.168.10.1")));
         internalHostListener.event(
                 new HostEvent(HostEvent.Type.HOST_ADDED, host));
 
@@ -266,7 +266,7 @@
 
         // Set up test expectation
         reset(hostService);
-        expect(hostService.getHostsByIp(anyObject(IpPrefix.class))).andReturn(
+        expect(hostService.getHostsByIp(anyObject(IpAddress.class))).andReturn(
                 new HashSet<Host>()).anyTimes();
         hostService.startMonitoringIp(IpAddress.valueOf("192.168.20.1"));
         replay(hostService);
@@ -286,7 +286,7 @@
                 new HostLocation(
                         SW2_ETH1.deviceId(),
                         SW2_ETH1.port(), 1),
-                        Sets.newHashSet(IpPrefix.valueOf("192.168.20.1/32")));
+                        Sets.newHashSet(IpAddress.valueOf("192.168.20.1")));
         internalHostListener.event(
                 new HostEvent(HostEvent.Type.HOST_ADDED, host));