update kwargs with args in wrap_instance_fault

fix bug: 1067254

If argument 'instance' is in args rather than kwargs,
we will get a KeyError exception which will cover up
the real exception. So, we update kwargs with the
values from args first. then, we can get 'instance'
from kwargs easily.

Change-Id: Ife89f9e9629e4b581d96289434e9ececced17915