Add migration with data test for migration 151

Before the 151 migration test is run, _prerun_151 populates the task_log
table with generated date and time in string format for period_beginning and
period_ending. The _check_151 function checks that the migration from string
to DateTime worked as expected.

Partially implements: blueprint migration-testing-with-data

Change-Id: I6d354741a75804bc490ffefde04c5925dd1a2a90
Use connection_info on resize

During finish_migration the manager calls initialize_connection but doesn't
update the block_device_mapping with the (potentially new) connection_info
returned.

This can cause the bdm to get out of sync, the volume to fail to attach, and
the resize to fail.

Fixes bug #1076801

Change-Id: Ie49ccd2138905e178843b375a9b16c3fe572d1db
Adds API Sample tests for FlavorAccess extension.

Partially implements blueprint nova-api-samples
Fixes bug 1091741

Change-Id: I65bb9e508996417bdcdc9ec87997df5373c06bad
Remove dead variable assignment in compute manager

The assigement of 'db_power_state' in '_sync_power_state' is
never used before it is overwritten a few lines later

Blueprint: compute-driver-events
Change-Id: I0a7e88fc7c3067a09b0a05a643ae4e6d40a11488
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Split out body of loop in _sync_power_states in compute manager

The _sync_power_states method in the compute manager iterates
over all instances in the DB, synchronizing their power
states. The introduction of async events to the compute
drivers requires a method for synchronizing the power state
of a single instance at a time. Split out the body of the
loop in _sync_power_states to a method _sync_instance_power_state

Blueprint: compute-driver-events
Change-Id: I5eee72b39f765a2444388005fabba2cff7ff4b29
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Merge "Add migration with data test for migration 151"
Merge "Remove dead variable assignment in compute manager"
Merge "Split out body of loop in _sync_power_states in compute manager"
Merge "Adds API Sample tests for FlavorAccess extension."
Merge "Use connection_info on resize"