glx: Add an error message when a direct renderer's createScreen() routine fails

glx: Add an error message when a direct renderer's createScreen() routine fails
because no matching fbConfigs or visuals could be found.

Nearly all the error cases in *createScreen() issue an error message to diagnose
the failure to initialize before branching to handle_error.  The few remaining
error cases which don't should probably do the same.

(At the moment, it seems this can be triggered in drisw with an X server which
reports definite values for MAX_PBUFFFER_(WIDTH|HEIGHT|SIZE), because those
attributes are checked for an exact match against 0.)

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>