P2P: Update D-Bus network object semantics during group formation

P2P: Update D-Bus network object semantics during group formation

Do not emit network objects during P2P group formation since such
network objects can confuse certain apps. Instead, a persistent group
object is created to allow apps to keep track of persistent groups.
Persistent group objects only represent the info needed to recreate the
group.

Also fixes a minor bug in the handling of persistent group objects
during WPS operations.

Signed-off-by: Jayant Sane <jayant.sane@intel.com>