dispatch: lessen deselect() constraints
dispatch: lessen deselect() constraints

Allow callers to pass deselected events to deselect(). We still
disallow passing -1 (or anything that was never enabled on the FD), but
we now explicitly allow repeated deselection.

Signed-off-by: David Herrmann <fb53b2ddb8d141e0cb39d7c67c2f81b6bc2eb0f7@gmail.com>

bus1/dbus-broker