4653: Add more helpful message when getting global classad throws
4653: Add more helpful message when getting global classad throws

If getting the globals classad throws an exception, it probably means
that Condor's not running.  Also a re-raise was added since the
factory was dying at the next step anyway (since the classad
dict was undefined if the exception was caught).

bbockelm/glideinWMS,bbockelm/glideinWMS,bbockelm/glideinWMS,bbockelm/glideinWMS