Update play-scala-mongodb to play2-scala-mongodb for testing in Travis

.travis.yml

@@ -136,7 +136,7 @@ env:
     - "TESTDIR=Scala/lift-stateless"
     - "TESTDIR=Scala/plain"
     - "TESTDIR=Scala/play-activate-mysql"
-    - "TESTDIR=Scala/play-scala-mongodb"
+    - "TESTDIR=Scala/play2-scala-mongodb"
     - "TESTDIR=Scala/play2-scala"
     - "TESTDIR=Scala/scalatra"
     - "TESTDIR=Scala/scruffy"