Remove the local onos/core/Pair.java class and replace it with
the corresponding "org.apache.commons.lang3.tuple.Pair" from Apache.

Usage differences:
 * "new Pair<>(a, b)" -> "Pair.of(a, b)"
    Note that "Pair.of()" returns immutable pair by definition: ImmutablePair

 * "Pair.getFirst()" -> "Pair.getLeft()"
   "Pair.getSecond()" -> "Pair.getRight()"

Also, few replacements for HashMap and similar containers:
"new HashMap<Foo, Bar>()" -> "new HashMap<>()"

Change-Id: I7a3d8a34dac37c672f0d1779f83f50dfeba8dec7
diff --git a/src/main/java/net/onrc/onos/core/flowprogrammer/IFlowPusherService.java b/src/main/java/net/onrc/onos/core/flowprogrammer/IFlowPusherService.java
index e94119a..25162aa 100644
--- a/src/main/java/net/onrc/onos/core/flowprogrammer/IFlowPusherService.java
+++ b/src/main/java/net/onrc/onos/core/flowprogrammer/IFlowPusherService.java
@@ -6,8 +6,8 @@
 import net.floodlightcontroller.core.internal.OFMessageFuture;
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.onrc.onos.core.intent.FlowEntry;
-import net.onrc.onos.core.util.Pair;
 
+import org.apache.commons.lang3.tuple.Pair;
 import org.projectfloodlight.openflow.protocol.OFBarrierReply;
 import org.projectfloodlight.openflow.protocol.OFMessage;