Be more selective about openids in bug script.

Look for login.launchpad.net openids for the openid->username
mapping.  Some users have other openids that won't work.

Change-Id: I6201d33e553120548e9d910830dfe23072b65b63
Reviewed-on: https://review.openstack.org/19502
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins