Fix high priority findbugs reported issues

Fixed some code that was reporting findbugs errors

Implemented a suppression mechanism for findbugs
reported errors and a suppression file.

Change-Id: Ie8a2e84cc57ec6ddfa14d782ee89feb095b9dd59
diff --git a/openflow/ctl/src/main/java/org/onlab/onos/openflow/controller/impl/RoleManager.java b/openflow/ctl/src/main/java/org/onlab/onos/openflow/controller/impl/RoleManager.java
index 734e0ba..51e90e5 100644
--- a/openflow/ctl/src/main/java/org/onlab/onos/openflow/controller/impl/RoleManager.java
+++ b/openflow/ctl/src/main/java/org/onlab/onos/openflow/controller/impl/RoleManager.java
@@ -216,7 +216,7 @@
                     + "Switch: {}. "
                     + "This controller has no current role for this sw. "
                     + "Ignoring ...", new Object[] {rri,
-                            sw.getStringId(), });
+                            sw == null ? "(null)" : sw.getStringId(), });
             return RoleRecvStatus.OTHER_EXPECTATION;
         }
 
diff --git a/openflow/ctl/src/main/java/org/onlab/onos/openflow/drivers/impl/OFSwitchImplCPqD13.java b/openflow/ctl/src/main/java/org/onlab/onos/openflow/drivers/impl/OFSwitchImplCPqD13.java
index f5aa0d4..0905f43 100644
--- a/openflow/ctl/src/main/java/org/onlab/onos/openflow/drivers/impl/OFSwitchImplCPqD13.java
+++ b/openflow/ctl/src/main/java/org/onlab/onos/openflow/drivers/impl/OFSwitchImplCPqD13.java
@@ -155,7 +155,7 @@
 
     @Override
     public void processDriverHandshakeMessage(OFMessage m) {
-        if (!startDriverHandshakeCalled || !startDriverHandshakeCalled) {
+        if (!startDriverHandshakeCalled) {
             throw new SwitchDriverSubHandshakeNotStarted();
         }
         if (driverHandshakeComplete.get()) {