dom0: provide explicit config path to xl save

The default behaviour is to take it from /var/lib/xen, where files are created
with mode 600, so unable to read it as normal user.

dom0/restore/qubes_prepare_saved_domain.sh

@@ -53,7 +53,7 @@ touch $QMEMMAN_STOP
 xl mem-set $1 $(($MEM/1000))
 sleep 1
 touch $2
-if ! xl save $1 $2 ; then 
+if ! xl save $1 $2 $VMDIR/$1.conf; then 
 	rm -f $QMEMMAN_STOP
 	exit 1
 fi