obmc-initfs: run update as a sub-script

The update script has replicated logic to do the final reboot, kexec,
halt, or poweroff command.  Instead of transferring control via exec
just call it as a normal command, and return to shutdown for the
final mounted fs debug print and command.

Signed-off-by: Milton Miller <miltonm@us.ibm.com>
diff --git a/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh b/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
index 32e83e6..face06d 100755
--- a/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
+++ b/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
@@ -92,19 +92,12 @@
 	umount $rwdir
 fi
 
-# Execute the command systemd told us to ...
-if test -d /oldroot && test -x "/sbin/$1" && test -f "/sbin/$1"
-then
-	if test "$1" == kexec
-	then
-		/sbin/$1 -f -e
-	else
-		/sbin/$1 -f
-	fi
-fi
+exit
 
+# NOT REACHED without edit
+# NOT REACHED without edit
 
-echo "Execute ${1-reboot} -f if all is ok"
+echo "Flash completed.  Inspect, cleanup and reboot -f to continue."
 
 export PS1=update-sh#\ 
 exec /bin/sh