Clean imports in code
Clean imports in code

In some part in the code we import objects. Openstack style
guideline recommends to import only modules.

http://docs.openstack.org/developer/hacking/#imports

Change-Id: I54138598b2556c080b1c61753db505878a9391d0

eayunstack/neutron,cloudbase/neutron,mahak/neutron,noironetworks/neutron,cloudbase/neutron,sebrandon1/neutron,noironetworks/neutron,mahak/neutron,openstack/neutron,huntxu/neutron,mahak/neutron,openstack/neutron,igor-toga/local-snat,igor-toga/local-snat,eayunstack/neutron,openstack/neutron,huntxu/neutron,sebrandon1/neutron