Bug 1108017: Load .ini modules on php setup

If user is creating quickstart with a oneliner e.g.: 
`rhc app create magento zend-6.1 mysql-5.1 --from-code=https://github.com/openshift/magento-example`
the deployment will fail cause the deploy script is expects that all needed modules are in the `openshift.ini` file and loaded.

Now the modules will be load also upon the setup phase.

Also renamed the `php_module_scan` file into `php_module_prepare` and moved the module load logic into that file, so it can be used also upon the setup phase.
This is only used in `enable_modules` at lines 75 and 84. Instead of exporting the variable here, maybe use `local SYSTEM_PHP_D_DIR=$(system_php_dir)` at the start of `enable_modules`?