mod_lua: Remove dead code left over from the old code cache.

The code that used this was commented out in r721594, then removed entirely in
r728497, and finally a commit was made intending to remove the last traces of
the code cache in r1200513, but this initialization lived on anyway.

* modules/lua/mod_lua.c
  (create_server_config): Remove unused empty hash and rwlock for hash.

* modules/lua/mod_lua.h
  (ap_lua_server_cfg): Remove unneeded hash and rwlock entries.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1606836 13f79535-47bb-0310-9956-ffa450edef68