Fix Package name for ubuntu + a hack

supercede #51 #36 

1. Fixes package names such that cookbook user can use the attributes to control installation
2. Fixes ubuntu package name to close issues like #86 #46  etc.
3. adds a **hack**

#### hack ####
Due to ubuntu using upstart, I added a hack in `mongodb::default` that would stop the mongo server (if the upstart file is found) and remove the said upstart file.  The hack should only ever run once (unless something keeps recreating the upstart file).

Ubuntu users who are using the cookbooks will not be affected since they have been installing via the `mongodb::10gen` which would not have used the upstart file.

I think the only reasonable `clean` alternative would be to add the ubuntu upstart file into templates, but it would need a reworking of the mongod definition, so it would have to wait for now.