Enable checkstyle rule to verify method names

Enabled checkstyle rule "MethodName" which checks
if method names adhere to a naming convention and
fixed the violations it found.

Change-Id: I87448a1fa857e78f33c42090d485bf21a8986ba7
diff --git a/src/main/java/net/onrc/onos/core/datastore/IKVClient.java b/src/main/java/net/onrc/onos/core/datastore/IKVClient.java
index 0fa1cbd..c2d9e35 100644
--- a/src/main/java/net/onrc/onos/core/datastore/IKVClient.java
+++ b/src/main/java/net/onrc/onos/core/datastore/IKVClient.java
@@ -161,6 +161,6 @@
      * Version number which represents that the object does not exist, or has
      * never been read the DB before.
      */
-    public long VERSION_NONEXISTENT();
+    public long getVersionNonexistant();
 
 }