Preserve the install options and pass them to core libraries

Hello.
When I install MCollective with ```install.rb``` and specify the ```configdir``` option, I think it should search for config files in the directory that  I specified. But in fact it still tries to load the default ```/etc/mcollective/server.cfg```, which is a bit confusing. 
I think the install.rb should preserve the custom install options and pass them to MCollective's core library.