ISPConfig ignored conf-costume for mailman
ISPConfig ignores conf-custom for mailman.
-rwxr-x--- 1 ispconfig ispconfig 4393 Feb 1 10:49 /usr/local/ispconfig/server/conf-custom/mm_cfg.py.master -rwxr-x--- 1 ispconfig ispconfig 4417 Jan 12 23:08 /usr/local/ispconfig/server/conf/mm_cfg.py.master
And ISPC uses the original conf.