MODCLUSTER-430, Re-creating proxy_module configuration structures in ord...

...er to have them unique, not being shared with the main_server. Furthermore, some minor httpd 2.2.x compatibility fix and additional logging. See [pull/119](https://github.com/modcluster/mod_cluster/pull/119) for details...
Unused variable. It has been deleted from 1.3.x (master) already.