nickserver should listen only on 127.0.0.1

because nickserver has a ssl proxy-pass from apache to the local port, it shouldn't be running on 0.0.0.0, which it is now:

tcp 0 0 0.0.0.0:64250 0.0.0.0:* LISTEN 10922/ruby

(from redmine: created on 2013-05-29, closed on 2015-06-16)