[SSSD] [PATCH] fix DBusWatch handling

[Simo Sorce]

After some playing around with Stephen patch and adding some debugging I
finally understood how DBUS likes to deal with watches.

We erroneously assumed that DBUS would add only one watch per FD.
It doesn't, instead it always adds 2 watches.
One to catch read events and one to catch write events.

It then proceed to always keep one of the 2 disabled when the other is
enabled, and it always toggles both when it needs to reverse access to
the file descriptor.

The following patch keeps track of sbus-watches/fd pairs and allocate
both DBusWatches to the same structure.

So far testing seem to confirm this approach works as expected.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York