Fix issues found by FindBugs: ICAST_INTEGER_MULTIPLY_CAST_TO_LONG

http://findbugs.sourceforge.net/bugDescriptions.html#ICAST_INTEGER_MULTIPLY_CAST_TO_LONG

Change-Id: Ia7ef18ad5f62300bf74cc30050be018be5c585fc
diff --git a/src/main/java/net/onrc/onos/core/linkdiscovery/internal/LinkDiscoveryManager.java b/src/main/java/net/onrc/onos/core/linkdiscovery/internal/LinkDiscoveryManager.java
index 9b913c1..adcacd8 100644
--- a/src/main/java/net/onrc/onos/core/linkdiscovery/internal/LinkDiscoveryManager.java
+++ b/src/main/java/net/onrc/onos/core/linkdiscovery/internal/LinkDiscoveryManager.java
@@ -1512,7 +1512,7 @@
                 // Timeout the unicast and multicast LLDP valid times
                 // independently.
                 if ((info.getUnicastValidTime() != null) &&
-                        (info.getUnicastValidTime() + (this.LINK_TIMEOUT * 1000) < curTime)) {
+                        (info.getUnicastValidTime() + (1000L * this.LINK_TIMEOUT) < curTime)) {
                     info.setUnicastValidTime(null);
 
                     if (info.getMulticastValidTime() != null) {