MT#62787 Support NVMe disks in autodetection code

We had to revert commit 2974f71127,
as we're relying on the /sys/block autodetection code in our VM
builds that don't specify the target disk explicitly.

So instead let's reintroduce the code, but also support
NVMe disks and make the code more generic WRT sda vs vda.

While at it, also report a message whenever we're running through this
autodetection code.

Change-Id: I39fe04def1694f127a99c97f91fabc2768fec1c7

templates/scripts/includes/deployment.sh

@@ -1798,20 +1798,17 @@ fi
 if [ -n "$TARGET_DISK" ] ; then
   export DISK="${TARGET_DISK}"
 else # otherwise try to find sane default
-  if [ -L /sys/block/vda ] ; then
-    export DISK=vda # will be configured as /dev/vda
-  else
-    # in some cases, sda is not the HDD, but the CDROM,
-    # so better walk through all devices.
-    for i in /sys/block/sd*; do
-      if grep -q 0 "${i}/removable"; then
+  for i in /sys/block/sd* /sys/block/vd* /sys/block/nvme*n* ; do
+    # device might not be a HDD, but a CDROM or a removable device
+    if grep -q 0 "${i}/removable" 2>/dev/null; then
       DISK=$(basename "$i")
       export DISK
       break
     fi
   done
+  echo "NOTE: used autodetection code to assigning disk '${DISK}'"
 fi
-fi
+
 if [[ -n "${SWRAID_DISK1}" ]] && [[ -z "${SWRAID_DISK2}" ]] ; then
   die "Error: swraiddisk1 is set, but swraiddisk2 is unset."
 elif [[ -z "${SWRAID_DISK1}" ]] && [[ -n "${SWRAID_DISK2}" ]] ; then