Adding unit test for Role Changing code in Controller and OFSwitchImpl.

build.xml

lib/org.easymock_2.5.2.jar

src/main/java/net/floodlightcontroller/core/IOFSwitch.java

...va/net/floodlightcontroller/core/internal/Controller.java

...et/floodlightcontroller/core/internal/OFChannelState.java

.../net/floodlightcontroller/core/internal/OFSwitchImpl.java

...a/net/floodlightcontroller/core/internal/RoleChanger.java

...et/floodlightcontroller/core/internal/ControllerTest.java

...t/floodlightcontroller/core/internal/RoleChangerTest.java