Unit tests for the OpenFlow controller class

Change-Id: I14a6e2810ec15edfccb309ab94dabe96670f4026
diff --git a/openflow/ctl/src/main/java/org/onosproject/openflow/controller/impl/Controller.java b/openflow/ctl/src/main/java/org/onosproject/openflow/controller/impl/Controller.java
index 69c0616..d9848be 100644
--- a/openflow/ctl/src/main/java/org/onosproject/openflow/controller/impl/Controller.java
+++ b/openflow/ctl/src/main/java/org/onosproject/openflow/controller/impl/Controller.java
@@ -94,7 +94,7 @@
     protected String tsLocation;
     protected char[] ksPwd;
     protected char[] tsPwd;
-    private SSLEngine serverSSLEngine;
+    protected SSLEngine serverSSLEngine;
 
     // Perf. related configuration
     protected static final int SEND_BUFFER_SIZE = 4 * 1024 * 1024;