Not really needed at this point, but will be once touch support is added.
Since grabs are now expected to be allocated/freed with AllocGrab and
FreeGrab, CopyGrab must increase the refcount and duplicate the modifier
masks. Until the callers are switched to use FreeGrab, this introduces
memleaks.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>