Add DB query to get in-progress migrations.
Add DB query to get in-progress migrations.

Adds DB query to get in-progress migrations.  This will be needed
by resource tracker to get more accurate usage values around inbound
and outbound resizes.

bug 1065267

Change-Id: Ib111002c70aa16e404c6e2c3fcb4ad234177ce91

n0ano/gantt,n0ano/gantt