Use udevadm if available otherwise use udevtrigger/udevsettle

Moving forward udevadm {trigger/settle} replaced udevtrigger/udevsettle
as the correct interface to use.  However, since we need to work in
both environments for testing check and see if udevadm is available.
If it is then use it.  If it is not fall back to the legacy interface.

scripts/common.sh

@@ -44,6 +44,7 @@ RMMOD=${RMMOD:-/sbin/rmmod}
 INFOMOD=${INFOMOD:-/sbin/modinfo}
 LOSETUP=${LOSETUP:-/sbin/losetup}
 SYSCTL=${SYSCTL:-/sbin/sysctl}
+UDEVADM=${UDEVADM:-/sbin/udevadm}
 
 die() {
 	echo -e "${PROG}: $1" >&2
@@ -210,8 +211,13 @@ udev_setup() {
 
 	cp -f ${SRC_PATH} ${DST_PATH}
 
-	udevadm trigger
-	udevadm settle
+	if [ -f ${UDEVADM} ]; then
+		${UDEVADM} trigger
+		${UDEVADM} settle
+	else
+		/sbin/udevtrigger
+		/sbin/udevsettle
+	fi
 
 	return 0
 }