The "check configs" part of the message is useless for the majority of
users who are unlikely to have access to the server's configuration, so
drop that. Reword the message to be more consistent with the ones when
the 'is:private' 'is:started' and 'is:wip' operators are not supported.
Change-Id: I93ad6ca19134bb7f80e2e263126419ef14484533