Load pry only if present
Load pry only if present

Previous to this commit, the pry gem was loaded as part of the v2 provider for
ec2_instance. This breaks on any system without pry installed. This commit
attempts to load pry and then continues if it recieves a load error.

puppetlabs/puppetlabs-aws,puppetlabs/puppetlabs-aws,daveseff/puppetlabs-aws,daveseff/puppetlabs-aws