Remove binding:profile update from Mellanox ML2 MD

Remove temporary work-around that populates physical_network in
binding:profile. Now when both neutron and nova use binding:vif_details
to pass attributes to plug neutron port, this work-around is not nequired.
Remove related temporary code from ML2 plugin.

Change-Id: Ib37203af396f31080b1b27b500a571c20917f5a4
Closes-Bug: 1360762
Merge "Remove binding:profile update from Mellanox ML2 MD"