Pass configured auth strategy to neutronclient

When the token is invalid Nova emits a log trace about an
unknown auth strategy (caused by neutron client). This is a
red herring and is only masking the fact that the token was
unable to be validated in the first place.

Partial-bug: 1297309

Change-Id: Ia3801f80c7ca18674fcf46b5270aa04f6c8c9331
(cherry picked from commit fdd689c146713d18eb901d6f3ec986cdd11d13fe)
Merge "Pass configured auth strategy to neutronclient" into stable/icehouse