time.strptime's caching of its locale object was being recreated when the

time.strptime's caching of its locale object was being recreated when the
locale changed but not used during the function call it was recreated during.

The test in this checkin is untested (OS X does not have the proper locale
support for me to test), although the fix for the bug this deals with
was tested by the OP (#1290505).  Once the buildbots verify the test at least
doesn't fail it becomes a backport candidate.