Merge pull request #40 from wtogami/ontargetuserfix

Fix --user in --help to display how the command actually works

libexec/on-target

@@ -10,7 +10,7 @@ usage() {
   echo
   cat << EOF
   --help		display this help and exit
-  --user=U  run as U instead of ubuntu
+  --user <username>	run as <username> instead of ubuntu
 EOF
 }