Add response_parser to the gemspec.
Add response_parser to the gemspec.

Updated the gemspec by running 'rake gemspec'.

This fixes upstream excon RPM builds.

hammerdr/excon,cloudfoundry-incubator/excon,mahemoff/excon,TheNeatCompany/excon,excon/excon,ilackarms/excon,wadetandy/excon,liftforward/excon