firstboot: Send the output to the console as well as to the log file.

For systemd:
Currently stdout+stderr go to the journal (these are effectively
empty unless there are gross errors).  The output of the commands
goes to the log file.

With this change, the output goes to the journal, the console and
the log file.

For SysV-init:
Currently stdout+stderr go to the console (but these are effectively
empty).  The output of the commands goes to the log file.

With this change, the output goes to the console and the log file.

mllib/firstboot.ml

@@ -45,16 +45,16 @@ let firstboot_sh = sprintf "\
 d=%s/scripts
 logfile=~root/virt-sysprep-firstboot.log
 
-echo \"$0\" \"$@\" >>$logfile
-echo \"Scripts dir: $d\" >>$logfile
+echo \"$0\" \"$@\" 2>&1 | tee $logfile
+echo \"Scripts dir: $d\" 2>&1 | tee $logfile
 
 if test \"$1\" = \"start\"
 then
   for f in $d/* ; do
     if test -x \"$f\"
     then
-      echo '=== Running' $f '===' >>$logfile
-      $f >>$logfile 2>&1
+      echo '=== Running' $f '===' 2>&1 | tee $logfile
+      $f 2>&1 | tee $logfile
       rm -f $f
     fi
   done
@@ -71,6 +71,8 @@ Before=prefdm.service
 Type=oneshot
 ExecStart=%s/firstboot.sh start
 RemainAfterExit=yes
+StandardOutput=journal+console
+StandardError=inherit
 
 [Install]
 WantedBy=default.target