Log the traceback in _handle_keystone_exception

Some errors were logged without a traceback because they were
logged as a warning instead.

Change-Id: I68595e4e2c37279585f0434a173596e43e047004
Related-Bug: #1965316

keystone/server/flask/application.py

@@ -81,10 +81,8 @@ def _handle_keystone_exception(error):
         LOG.warning(
             "Authorization failed. %(exception)s from %(remote_addr)s",
             {'exception': error, 'remote_addr': flask.request.remote_addr})
-    elif isinstance(error, exception.UnexpectedError):
-        LOG.exception(str(error))
     else:
-        LOG.warning(str(error))
+        LOG.exception(str(error))
 
     # Render the exception to something user "friendly"
     error_message = error.args[0]