Simplifying regex for script download

configs/releng/airootfs/root/.automated_script.sh:
Using only one regex to match http://, https:// or ftp:// endpoints.

configs/releng/airootfs/root/.automated_script.sh

@@ -15,7 +15,7 @@ automated_script ()
     local script rt
     script="$(script_cmdline)"
     if [[ -n "${script}" && ! -x /tmp/startup_script ]]; then
-        if [[ "${script}" =~ ^http:// || "${script}" =~ ^ftp:// ]]; then
+        if [[ "${script}" =~ ^((http|https|ftp)://) ]]; then
             wget "${script}" --retry-connrefused -q -O /tmp/startup_script >/dev/null
             rt=$?
         else