Pass instance to _set_instance_error_state

This builds on commit 77a8478 so that _error_out_instance_on_exception
can pass the instance to _set_instance_error_state.  The next change in
the series will pass the instance down to _instance_update so if we have
an instance object we can avoid the direct call to conductor for state
changes and just update the instance object directly, which allows us to
remove instance.refresh() in the tests to pick up out-of-band database
updates on instance objects.

Part of blueprint compute-manager-objects-juno

Change-Id: I0a4607d368d3c226ca5a60d017d27c199c0dfe89
Merge "Pass instance to _set_instance_error_state"