Admiller/oo exec ruby

I updated oo-exec-ruby to handle multiple versions of ruby, this should work for all scenarios that I believe us to support. I also changed oo-mco since that invocation of oo-exec-ruby seemed unnecessary because it relies upon RHSCL ruby193 anyways.

@sosiouxme @detiber - please review

[test]
With my patch to oo-exec-ruby, if this were run on a machine with a newer ruby version installed then it will default to the system ruby and that mco command would fail because the LD_LIBRARY_PATH would be wrong. Let me re-think this, I can probably improve on that so it can handle both cases.