#555 change "apache::mod::passenger" to support overriding all parameters expected by "apache::mod".

apache::mod::passenger did not accept/pass (optional) module parameters to  apache::mod,
thus preventing overriding the auto-generated module parameters.  Without this option
apache::mod::passenger could not be used in conjunction with passenger modules generated
outside the OS package system (in particular, when compiled via 
passenger-install-apache2-module), as those are output to different paths.  This patch
enables overriding all parameters expected by "apache::mod", and includes spec coverage.