bdist_rpm should make an RPM with all dependencies declared.

The first commit simply adds a setup.cfg that causes bdist_rpm to add the appropriate "requires" line to the spec. 

The second commit is a bit of a hack. Because aminator needs a fairly recent version of boto, and the version available as a system RPM in CentOS 6 is quite old, I've added an "easy_install boto" to the `post_install`. This feels a bit off, but I can't think of a better way...