Stored metrics into compute_nodes as a json dictionary

The compute manager uses plugins to get the metrics information of each node.
And then sends and stores in DB for the scheduler to read and do scheduling.

The patch reuses table compute_nodes and adds a new TEXT column to store the
metric data as a json dictionary.

This is part of the blueprint utilization-aware-scheduling and the
blueprint generic-host-state-for-scheduler.

Change-Id: I4d20565567e9907cfcc92b1c1b15f3b35a806797
Signed-off-by: Shane Wang <shane.wang@intel.com>
Fix migration 185 to work with old fkey names

Migration 133_folsom.py accidentally changed the name of the FK
constraint on instance_info_caches from instance_info_caches_ibfk_1
to instance_info_caches_instance_uuid_fkey and on virtual_interfaces
from virtual_interfaces_ibfk_1 to
virtual_interfaces_instance_uuid_fkey meaning databases who have
upgraded from before folsom have the old fkey.

This patch adds a check for those with the old fkey name to make sure
it is dropped before changing unique constraints (as is required by
MySQL). It also fixes the fkey name to be as defined in 133 if it
wasn't before (which will persist on downgrade being consistent with
those who have come in after folsom).

Closes-Bug: #1245502

Change-Id: Ib0dcd04fcb9ed776c76d40561181abad2e14f76f
Replace assertEquals with assertEqual - tests/etc

The method assertEquals has been deprecated since python 2.7.
http://docs.python.org/2/library/unittest.html#deprecated-aliases

Also in Python 3, a deprecated warning is raised when using assertEquals
therefore we should use assertEqual instead.

This is part of blueprint assertequal

Change-Id: I5ecb36332b9353b7010a4f977813ff0295738014
Merge "Replace assertEquals with assertEqual - tests/etc"
Merge "Fix migration 185 to work with old fkey names"
Merge "Stored metrics into compute_nodes as a json dictionary"