[C++] Added missing cleanup in CcMessageRouterTest
[C++] Added missing cleanup in CcMessageRouterTest

* Added removeNextHop in helper method (which is called twice
  in single test case) since otherwise routing entries still exist

Change-Id: I6e6b32077682467c123e33b6884d4330327e913a

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr