Addressed Checkstyle and PMD violations in the registry module.

Note some PMD errors can't be cleaned up because the curator API throws
raw Exception on many methods. PMD complains about catching raw Exception.

Change-Id: I974e3e713417d71de8fcee3833d53ab003a71eae
diff --git a/src/main/java/net/floodlightcontroller/core/module/FloodlightModuleException.java b/src/main/java/net/floodlightcontroller/core/module/FloodlightModuleException.java
index 8519a3c..e4232fc 100644
--- a/src/main/java/net/floodlightcontroller/core/module/FloodlightModuleException.java
+++ b/src/main/java/net/floodlightcontroller/core/module/FloodlightModuleException.java
@@ -3,7 +3,11 @@
 public class FloodlightModuleException extends Exception {
     private static final long serialVersionUID = 1L;
 
-    public FloodlightModuleException(String error) {
-        super(error);
+    public FloodlightModuleException(String message) {
+        super(message);
+    }
+
+    public FloodlightModuleException(String message, Throwable cause) {
+        super(message, cause);
     }
 }