Sync scheduler.filters module from oslo-incubator

Sync scheduler.filters module from oslo-incubator

The scheduler.filters module hasn't been updated since
January of 2014.  As a result there are a number of changes
that we should pull into Cinder's copy.

Current HEAD in OSLO:
---------------------
commit e589dde0721a0a67e4030813e582afec6e70d042
Date:  Wed Feb 18 03:08:12 2015 +0000
Merge "Have a little fun with release notes"

Changes merged with this patch by file:

__init__.py
- be81d6ba - Cleanup unused log related code

availability_zone_filter.py
- 4a47188e -  Allow filters to only run once per request if their data is static

capabilities_filter.py
- 2fbf5065 - Remove oslo.log code and clean up versionutils API
- dacc065a - Merge "Update oslo log messages with translation domains"
- 86707cd5 - Remove None for dict.get()
- fcf517d7 - Update oslo log messages with translation domains

extra_specs_ops.py
- ac17de97 - Use oslo_utils instead of deprecated oslo.utils
- 6ff6b4b4 - Switch oslo-incubator to use oslo.utils and remove old modules

ignore_attempted_hosts_filter.py
- 2fbf5065 - Remove oslo.log code and clean up versionutils API
- 39625e18 - Set pbr 'warnerrors' option for doc build
- dacc065a - Merge "Update oslo log messages with translation domains"
- 86707cd5 - Remove None for dict.get()
- fcf517d7 - Update oslo log messages with translation domains

json_filter
- 262279b1 - switch to oslo_serialization
- 6c706c5c - Delete graduated serialization files
- 86707cd5 - Remove None for dict.get()

Change-Id: Ida01f1a6518dcd3a977c524c15dfe9f6979a4ead