Ensure user metadata mapped for instance notifications

Fixes bug 1284073

For pollster-originated samples related to instances, we apply a
mapping to the user metadata so as to ensure that there are no
embedded periods in metadata keys and also to exclude any metadata
not matching the configured reserved namespace.

Now this logic is also applied to user metadata for samples derived
from instance-related notifications in order to avoid failures when
persisting these data in mongodb.

(cherry picked from commit ddeb54bb0d2c4203332a5ecc09a4aedfce353a4c)
Change-Id: I77eab59023fa23c5879b05c948bd4cb1db7fa177
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 ceilometer 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.

Conflicts:
	tox.ini

Change-Id: Ibc613d77ad52d5f7d8d613f3dd66ffba4117ff72
(cherry picked from commit 860a2852ca92df20fa886cec2e75d753ac6e18bb)
Merge "Set python hash seed to 0 in tox.ini" into stable/havana
Updated from global requirements

Change-Id: Iee84a0882e82784928418fecd83d862c0ce1e8c0
Merge "Ensure user metadata mapped for instance notifications" into stable/havana
Merge remote-tracking branch 'os/stable/havana' into final-stable-havana-fixes
Merge pull request #3 from retr0h/final-stable-havana-fixes

Final stable havana fixes