Set P2p statemachine's network manager before starting Wifi

Wifi statemachine starts P2p statemachine; which uses network management
service to (i.e. netd) to start p2p0 interface. But it only gets a
reference to network management service in conenctivityServiceReady().
Calling that later means there's a chance of a race between this
thread's setting of the network manager, and P2p statemachine thread's
usage of the same.

Bug: 11048296
Change-Id: If151026ed5fbb12db57ee7f9bdd47c67dd7142e5