Specifically wait for /dev/disk/by-label

When udev is populating the disk hierarchy, it can be a long time
before the 'by-label' is specifically ready.

Wait for that specific entry to come along before continuing to
check if there's an identity image.

confluent_osdeploy/el8/initramfs/usr/lib/dracut/hooks/pre-trigger/01-confluent.sh

@@ -41,7 +41,7 @@ mkdir -p /etc/confluent
 echo -n > /etc/confluent/confluent.info
 umask $oum
 TRIES=5
-while [ ! -e /dev/disk ] && [ $TRIES -gt 0 ]; do
+while [ ! -e /dev/disk/by-label ] && [ $TRIES -gt 0 ]; do
     sleep 2
     TRIES=$((TRIES - 1))
 done