neutron fixes from mainline

commit 87783c25af8dcd474e447287f51eeb3718e907c0
Author: Praneet Bachheti <praneetb@juniper.net>
Date:   Thu Jul 31 16:12:49 2014 -0700

    set mac_address correctly

commit dd351ae778b961a0fed19263ad8d313fd4090375
Author: Praneet Bachheti <praneetb@juniper.net>
Date:   Wed Jul 30 11:45:42 2014 -0700

     fix typo in ipam_update

commit 04a065157ce759d0fc05e76c03b8297e9a4ed8b9
Author: Praneet Bachheti <praneetb@juniper.net>
Date:   Tue Jul 29 10:18:23 2014 -0700

    port subnet update from R1.06
    - we do not support gateway_ip update

Change-Id: I027d1415aa51b403eb990c22d54294b9cf6f8496