Add in platform/tools/tradefederation/contrib to master manifest.

BUG: 36556899

default.xml

@@ -574,6 +574,7 @@
   <project path="tools/swt" name="platform/tools/swt" groups="notdefault,tools" />
   <project path="tools/test/connectivity" name="platform/tools/test/connectivity" groups="pdk" />
   <project path="tools/tradefederation/core" name="platform/tools/tradefederation" groups="pdk,tradefed" />
+  <project path="tools/tradefederation/contrib" name="platform/tools/tradefederation/contrib" groups="pdk,tradefed" />
 
   <repo-hooks in-project="platform/tools/repohooks" enabled-list="pre-upload" />