vdsm: packages: stop libvirtd before configure it

recent vdsm-tool is not stopping services.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=999853
Change-Id: I47c7222c75467ae9773459bbcdcae64cbc3c2989
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>