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: #1230279
Document pkiz as provider in config

The pkiz provider wasn't documented as an option in the sample
config file.

Change-Id: I2657f46cb02d5bf044c6b9974257b41a0e839995
Merge "Ignore broken endpoints in get_catalog"
Merge "Document pkiz as provider in config"