Fix no handlers could be found issue

This patch fixes the error message during
unit tests for 2 issues.

1) test_migrations tries to LOG and exception before
setUp is called because of the method decorator.

2) the hp_lefthand_rest_proxy tries to LOG an exception
for a missing import.

Change-Id: I11d2c9320c0a216b5795207488b906795d27b1e0
Closes-Bug: #1341752
Set python hash seed to 0 in tox.ini

New tox (>=1.7.0) sets a random python hash seed by default. This is
generally good for testing because it will help keep projects working
regardless of the hash seed, but cinder unittests don't currently pass
with a random hash seed so set it to the python default seed.

This change will allow us to use new tox again and remove the
restriction on tox<=1.6.1 to run unittests.

Redundant setenvs for specific test envs are removed to prevent them
from overriding the PYTHONHASHSEED value.

Note this change will need to be backported to the stable branches to
keep unittests there working with new tox as well.

Change-Id: Ia55031528d082a1b11da6890447c5584e9e27551
Merge "Fix no handlers could be found issue"
Merge "Set python hash seed to 0 in tox.ini"