Catch InstanceInLocked exception for rescue and instance metadata APIs

When VM is locked by nova, VM API should not execute.
There are so many api that cannot be executed when vm is locked.
rescue/unrescue
update_instance_metadata/delete_instance_metadata
the above APIs should be updated to catch InstanceIsLocked exception

Change-Id: Ic88f3d190894d4b65f54b34660efd9ae83fb0ee4
Closes-Bug: #1266960
Merge "Catch InstanceInLocked exception for rescue and instance metadata APIs"