clear claimed nodes (chef data) on node reset

Conflicts:

	crowbar_framework/app/models/provisioner_service.rb
Merge pull request #210 from jjacob512/pull-req-release-roxy-master-9e6df227c057867110afd0b49f9e77a11d92108e

merging batch of fixes from mesa-1.6 to roxy [3/3]