Fix chef gates, allow sudo for gem install and use ruby 1.9.1

* We need to install system gecode 3.x libraries which requires sudo.
move revoke sudo step to below the bundler-prep step to allow that.
* We need to use ruby 1.9.1.  A previous commit removed the ruby1.9.1
prefix (see bug)
* Cleanup repo to use common builders

Change-Id: I7622cd939a26c29712d89dded8d2657ce25f3a82
Closes-Bug: #1357439
Merge "Fix chef gates, allow sudo for gem install and use ruby 1.9.1"