Enable checkstyle trailing spaces rule

Enable the checkstyle rule that detects unneeded trailing spaces
and fix the violations of the rule.

Change-Id: I65567c87142c5a257f0230a55bc4376e770d416f
diff --git a/src/main/java/net/onrc/onos/apps/bgproute/RibUpdate.java b/src/main/java/net/onrc/onos/apps/bgproute/RibUpdate.java
index c9d48e7..58ebdf1 100644
--- a/src/main/java/net/onrc/onos/apps/bgproute/RibUpdate.java
+++ b/src/main/java/net/onrc/onos/apps/bgproute/RibUpdate.java
@@ -4,7 +4,7 @@
     private final Operation operation;
     private final Prefix prefix;
     private final RibEntry ribEntry;
-    
+
     public enum Operation {
         UPDATE,
         DELETE