Ignore broken endpoints in get_catalog

If an endpoint is created with a malformed URL then get_catalog would
throw a HTTP 500 error. With this change we ignore all malformed
endpoints.

Change-Id: Ibe9a8fa49f410f2a76a0df732247bd6813fc734b
Partial-bug: #1347862
(cherry picked from commit 8737b43d2cc9cbc1af1ea7a0fbff39f1b1c50747)
Merge "Ignore broken endpoints in get_catalog" into stable/icehouse