(maint) Stop testing against rubies < 2.0
(maint) Stop testing against rubies < 2.0

This commit removes ruby 1.8.7 and 1.9.3 from the travis test matrix. These
are very old ruby versions that we don't support anymore.

puppetlabs/marionette-collective,puppetlabs/marionette-collective,puppetlabs/marionette-collective,puppetlabs/marionette-collective,puppetlabs/marionette-collective,puppetlabs/marionette-collective