Bugfix ring_script.rb to parse recent ring-builder

This bugfix allows the ring_script.rb to parse output from
the havana versions (swift 1.10) of swift-ring-builder
successfully.

Change-Id: I98ed30837226c28fb90910c1ae117506dfe14f8c
Fixes-Bug: #1266922
Merge "Bugfix ring_script.rb to parse recent ring-builder"