I added a couple of ruby versions that I think are safe for us to test
against. I considered keeping 1.9.3 for backwards-compat testing, but
since 1.9.3 support isn't given upstream, I think it is best to just
RVM fails on machines with gpg installed. This fix checks for the
existence of gpg on the system and imports the appropriate key as
defined by the attribute. Use of a ruby_block will allow for some
code reuse in the LWRP release.