Move the registering of public IP for media transport (ICE)
at the right place: after its initialization.
Before, the ICE register method was silently return immediatly
without registering.

This has effect to give a better connection (real P2P) if possible.

A error log has also been added in the ICE publc IP register method
to detect such case.

Change-Id: If88a6801aa55833f687cd552033efe579ab29393