Move neutron_utils functions to neutron client

All uses of neutron_utils functions have been migrated to using
the neutron client plugin version.

Functions in neutron_utils are deprecated and will be deleted in the
next patch.

Change-Id: I1b00485bddffcb6b9dba2ac770668dde9d6a0d70
Merge "Move neutron_utils functions to neutron client"