When a script is a symbolic link to the 'no-wait.d' subdirectory, the
dispatcher now schedules it immediately and in parallel with other
no-wait scripts.
https://bugzilla.gnome.org/show_bug.cgi?id=746703
Most D-Bus interface name macros used "INTERFACE" in their name (eg,
NM_DBUS_INTERFACE), but a few used "IFACE" instead (eg,
NM_DBUS_IFACE_SETTINGS). Make them consistent.
To ensure that NetworkManager does not block needlessly for events
which have no scripts, require scripts that respond to blocking
events to opt into the action.
If there are no dispatcher scripts, don't bother dispatching any
events. This saves some time configuring networking if the event
would have no effect anyway.