Allow user to specify bootstrap gems.

[bradphelan]

For example the opscode aws cookbook requires aws gem but this gem is required in one of the aws cookbook libraries which is loaded before any dependency analysis is done. It is not possible to specify to install this gem via a cookbook. A work around would be allow this
to be specified in the clouds.rb

bootstrap_gems ['right_aws']

If given a few pointers I'd try to implement it myself but I just can't figure out how the DSL thingie is all wired up. For myself I just modified.

---

lib/cloud_providers/remote_instance.rb

50 'gem install chef ohai right_aws --no-rdoc --no-ri'

so it installs the right_aws gem. I couldn't figure out how to get info from the top level down to here.

regards brad