scripts: update gogs.service (#4223)

According to https://goo.gl/ea8k9K, it hurts nothing to use
nonexistent services but gains convenient for default settings.

scripts/systemd/gogs.service

@@ -2,11 +2,7 @@
 Description=Gogs
 After=syslog.target
 After=network.target
-#After=mysqld.service
+After=mariadb.service mysqld.service postgresql.service memcached.service redis.service
-#After=mariadb.service
-#After=postgresql.service
-#After=memcached.service
-#After=redis.service
 
 [Service]
 # Modify these two values and uncomment them if you have