Fix init script for Reply by email

lib/support/init.d/gitlab

@@ -288,7 +288,7 @@ print_status() {
   fi
   if [ "$mail_room_enabled" = true ]; then
     if [ "$mail_room_status" = "0" ]; then
-        echo "The GitLab MailRoom email processor with pid $spid is running."
+        echo "The GitLab MailRoom email processor with pid $mpid is running."
     else
         printf "The GitLab MailRoom email processor is \033[31mnot running\033[0m.\n"
     fi