Add refresh=True to get_available_nodes call in build_and_run_instance

The run_instance code path passes refresh=True to get_available_nodes in
order to get fresh data from that call.  The build_and_run_instance
patch doesn't pass that argument and therefore may not get the latest
data.  This ports the argument over to that path to prepare for using
build_and_run_instance.

Part of bp remove-cast-to-schedule-run-instance

Change-Id: If857fdb4125d4af656f86de3e963987dd32c208b
Merge "Add refresh=True to get_available_nodes call in build_and_run_instance"