Keep resizing&resized instances when compute init

During compute manager startup init_host is called. One of the
functions there is to delete instance data that doesn't belong
to this host i.e. _destroy_evacuated_instances.
But this function only checks if the local instance belongs to
the host or not. It doesn't check the task_state or vm_state.

In Resize function, user may want to revert or confirm the resize
operations so the instance on source and dest compute node should
be kept. so for RESIZE_MIGRATING, RESIZE_MIGRATED task states and
RESIZED vm state instances, they should be kept in compute node
when the compute restart. This patch adds check for the task
state and vm state before delete the instances.

Closes-Bug: #1330503

Change-Id: I723fa4a8823019391ea83aa189096531032adab1
Merge "Keep resizing&resized instances when compute init"