Raise an exception on put_message with no URL.
Raise an exception on put_message with no URL.

If put_message is called without a URL, raise an exception to make it
easier to track down the origin of the issue.

tcmitchell/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal