[AWARE] Add UID checking to WifiAwareNetworkSpecifier

Wifi Aware networks are per app - i.e. a requestor gets
a dedicated network. Change verifies that the only the
original requestor matches the created network (using UID).

Bug: 36053921
Test: Integration (sl4a) tests
Change-Id: I4ff3994731dd7ccb88e2bea333d1e6905b136f02