Add --catalog to service show

Shows endpoints from the service catalog rather than the system services.

Change-Id: I842916af9f7c0a76c4d3e27e419bf0fec059ec78
Merge branch 'image-v1' into dt-test
Merge branch 'identity-catalog' into dt-test
Merge branch 'limits-show' into dt-test
Merge branch 'volume-keystone' into dt-test