NAN: Support multiple instantiation per UID - introduce a client ID.
Add the concept of a client ID which is used to identify a specific
(one of several) clients in all API calls.
(cherry-pick of aa36f071,
Change-Id: I43f13d51bee8b57c6d0ba1174168288b8d6c21c5)
Bug: 26962024
Change-Id: I0e0ddf37ea9800ae97115d6af384b54b49a40d74
(cherry picked from commit 5155990c)