Fix status messages checks for neutron provider

W/o this change many of 'bad' status messages returned
from Neutron API wouldn't be noticed by neutron provider

The suggested fix is to add more status checks and
notifications (non-fatal ones) about Neutron API
inaccessibility.

Closes-bug: #1384097

Change-Id: I227cea60e2b2d2ec14a96ef8aeb43dfad263ff3b
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "Fix status messages checks for neutron provider"