Default the last parameter (state) in task_log_get to None

Change the method signature to match the other definitions
of task_log_get

Fixes LP# 1117263

Change-Id: I510c05d4520c579bf07953d9ed05d7a58e051695
Add regression testing tool

Tool detects if a gerrit patch contains tests to detect a regression

Usage: ./tools/regression_tester.py gerrit_review_number

Change-Id: I6353d1efda73fe5fc3098f928b6da9a28eb40590
Recache or rebuild missing images on hard_reboot

The primary purpose of this change is to provide the ability to
re-cache missing backing files on hard_reboot. The old
pre_block_migration function was already performing a very similar
operation. That function has been refactored to be idempotent and
renamed to _create_images_and_backing. The pre_block_migration
function is a wrapper, with some additional checking, around the
renamed function.

Image backend was also adjusted to look for either a missing backing
file or disk image, recaching or creating accordingly. It should
also be idempotent, never clobbering existing images.

Change-Id: Icf4c488d6db59e732b463d08d0606b428ee1e7b9
Move floating ip db access to calling side.

Most of the allocation for floating ips can be done on the calling
side, including finding the proper host to send the message to.
This saves us from making an rpc call for allocate/deallocate and
makes sure that we only need 1 call for associate/disassociate by
finding the proper host to send the message to immediately.

Getting exceptions to work properly required pulling in the helper
that was used by the conductor to regenerate exceptions that are
wrapped for rpc. Since this is now a shared class, it was moved
to utils.

Also a few config options were moved to avoid circular imports.

Part of blueprint optimize-nova-network

Change-Id: I6ec65b1f3e8d00cab778b10eec620760886567e0
Merge "Add regression testing tool"
Merge "Recache or rebuild missing images on hard_reboot"
Merge "Default the last parameter (state) in task_log_get to None"
Merge "Move floating ip db access to calling side."