Remove the usage of instance['extra_specs'].

Instance type extra specs is remove from instance dict, so use inst_type['extra_specs']
instead of instance['extra_specs'].

fix bug #1146253

Change-Id: I1d3542e5142f490269607b779daa507f9d7b36e4
Merge "Remove the usage of instance['extra_specs']."
Merge remote-tracking branch 'm_src_repo/master' into build-temp