bus: Fix restart crash with inotify read()
bus: Fix restart crash with inotify read()

Do not close inotify desciptors when restarting the server. This
may lead to crashes in glib.

Fixes crash in libglib/libgio with
GLib-GIO-ERROR : inotify read(): Bad file descriptor

See also src/tests/ibus-bus.c: start_exit_async():
    /* When `./runtest ibus-bus` runs, ibus-daemon sometimes failed to
     * restart because closing a file descriptor was failed in
     * bus/server.c:_restart_server() with a following error:
     *     "inotify read(): Bad file descriptor"

Test plan:
Run
$ ibus restart
several times. Without the patch ibus-daemon will crash occasionally.

BUG=https://github.com/ibus/ibus/pull/2148

fujiwarat/ibus,ibus/ibus,ibus/ibus,ibus/ibus,fujiwarat/ibus,ibus/ibus,fujiwarat/ibus,fujiwarat/ibus