Add update binding:profile with physical_network

Add temporary solution in order to support multiple physical networks
by mlnx ML2 MechanismDriver.
Due to non merged patches in nova that should support propagating
physical_network retrieved from port binding:profile attribute
to VIF/Network object.
The code will be removed once relevant nova patches are merged.
The code is disabled by default and should be enabled via
ml2_conf_mlnx.ini config file.

Change-Id: I815f9e28774efd47bccd1c57481e6ba89075792b
Closes-bug: #1291209
tests/unit: clean up notification driver

Some tests doesn't cleanup notification driver. So some tests can
run against unintended notification driver depending on execution order

Change-Id: I7dbed47153be66684827b2693bbc995dddfb4c1b
Related-Bug: #1281481
Partial-Bug: #1284549
Merge "tests/unit: clean up notification driver"
Merge "Add update binding:profile with physical_network"