Various fixes to htcondor ce tools

* https://jira.opensciencegrid.org/browse/SOFTWARE-1678
* https://jira.opensciencegrid.org/browse/SOFTWARE-1679
* Conditional for SEC_CLIENT_AUTHENTICATION_METHODS that we spoke about adding to the condor_ce_client_env_bootstrap.

I'm realizing I probably should've made separate pull requests for each issue...
I think you want:

if [ "X$_condor_blah" == "X" ]; then

no?  I seem to recall there's a bash gotcha looking at empty strings (CarlE might know; I'm horrible at bash)