P2P : Flush P2P scan results on group fomation failed event

P2P group fomation failed event removes the target device entry
from peers list in framework.If Group negotiation request comes
from supplicant, framework will drop request due to entry removal
in peers list.
To handle this situation, framework has to send P2P flush command upon
device entry removal, so that supplicant and framework will be in sync
with device information.

Change-Id: I738ea50706d337bcc7e33d07bac53aa26b18ca7a
CRs-Fixed: 610632