packaging: tune: iosched: modify udev trigger to change event

rhel initscripts does not distinguish where udev even comes from, so
triggering hotplug even in all cases.

change udev trigger to issue change event, as current initscripts
ignores this event.

current targeted udev rules handle change events so uneffected.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1005278
Change-Id: I626c30eb1f281cf14a753f657c9313144df1b0db
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>