Bug fix: Do not create groups as a side effect when revoking routes
Also changing pendingGroups to a cache that will automatically purge failed groups
Improving log messagesin several places

Change-Id: I6843a66d58e623259c7fd20ffe64d56a46d963f0
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/IcmpHandler.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/IcmpHandler.java
index 38293d0..aaa8d4c 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/IcmpHandler.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/IcmpHandler.java
@@ -272,7 +272,7 @@
     private void handleNdpRequest(NeighbourMessageContext pkt, HostService hostService) {
         // ND request for the gateway. We have to reply on behalf of the gateway.
         if (isNdpForGateway(pkt)) {
-            log.debug("Sending NDP reply on behalf of the router");
+            log.trace("Sending NDP reply on behalf of gateway IP for pkt: {}", pkt);
             sendResponse(pkt, config.getRouterMacForAGatewayIp(pkt.target()), hostService);
         } else {
             // NOTE: Ignore NDP packets except those target for the router