Explicitly set Ruby version for Jenkins tests
Explicitly set Ruby version for Jenkins tests

Set the `RBENV_VERSION` environment variable so that our Jenkins tests
run under Ruby version 2.1.2, the latest version supported by our
`travis.yml` which is used to run the spec tests.

Prior to this, Jenkins would implicitly use the system ruby version
(1.9.3) to run the tests.

gds-operations/vcloud-edge_gateway,gds-operations/vcloud-edge_gateway,gds-operations/vcloud-edge_gateway