Tested OK w/ Grails 2.3.5 through 2.4.3

Tested OK w/ Grails 2.3.5 through 2.4.3, except for three tests: two
related to no-grant-client tests where InvalidGrantException ends up in
OAuth2 Error page. The last (must include scope for [#grant_type])
breaks on client_credentials (result is 200 OK) and refresh_token,
which fails but for the wrong reason (missing refresh token)