Pinning Rubydora version to 1.6.5

Pinned the Rubydora version to 1.6.5 until we can configure
soft_delete to work with Rubydora versions greater than 1.7.0

HYDRASIR-236 #close
Merge pull request #422 from projecthydra/feature/217-rubydora-bug

Pinning Rubydora version to 1.6.5