Allow per-project configuration file.

RHC tools now look for the global (`/etc`) and local (`~/.openshift`) directories for the `express.conf` file.

In case when you run Origin on your machine, you need to use different libra_server. This could be solved by using` --config` attribute, but that is not really 'user-friendly' ;-)

This patch allows you to place the config file into:

`$PROJECT/.openshift/express.conf`

So you can overide the libra_server just for one project you want to test on origin.