common: Strip trailing slash from endpoints
Remove trailing slash from the endpoints' publicURL field in service definitions. These values end up in the response of POST /tokens, and, according to the keystone API, should not end in slash. A trailing slash breaks some clients, which do no proper checking before appending a suffix. Note that these URLs are not meant to act as a base path in the strict semantics of http://tools.ietf.org/html/rfc3986#section-5.2.3 . Suffixes should be merged into by a simple append (modulo catering for the joining slash). URLs are still configured as groups per prefix ending in a slash, eg: '^account/' and '^ui/'. Permanent redirects are added for all non-API endpoints (ui, helpdesk, admin, etc), so that `BASE_PATH/path' leads to `BASE_PATH/path/'.