reject focus-set attempt if desk flip to client's desk was rejected

reject focus-set attempt if desk flip to client's desk was rejected

in the case of recursive desk flips, toggling a desk's visibility may
erroneously send queued evas events to the client's frame object, leading
to a focus-set (mouse-based focus models) which triggers a desk flip
inside the original desk flip. this "inner" desk flip is spurious and
should be ignored