[COOK-2564] - Apache VirtualHost port in web_app

* Allow port in web_app config (e.g. server_port 8080)
* Default to first Apache Listen port if not defined
* Compile FastCGI module for RHEL-based platforms
* Rely on Apache lib dir from attributes instead of being statically defined

http://tickets.opscode.com/browse/COOK-2598
* Generate module list after compiling FastCGI for EL
* Clean-up (per https://github.com/opscode-cookbooks/apache2/pull/54)
Change 'else if' to 'elsif'
COOK-2598: Add whitespace to the code segment