Workaround the broken inheritance heriarchy of the L3RouterPlugin
Workaround the broken inheritance heriarchy of the L3RouterPlugin

An issue in neutron is making this class inheriting some
methods from l3_dvr_db.L3_NAT_with_dvr_db_mixin. As a workaround
we force it to use the original methods in the l3_db.L3_NAT_db_mixin
class.

Signed-off-by: Rosario Di Somma <73b2fe5f91895aea2b4d0e8942a5edf9f18fa897@dreamhost.com>

openstack/akanda-neutron,stackforge/akanda-neutron