1148919 - 148915 - remove traceback from log if user enters incorrect password

By logging an error rather than an exception, the traceback is left out of the logs. Fixes [BZ-1148919](https://bugzilla.redhat.com/show_bug.cgi?id=1148919) and [BZ-1148915](https://bugzilla.redhat.com/show_bug.cgi?id=1148915)
Since this method just calls _logger.error() it seems unnecessary. Can you just just _logger.error() everywhere instead?