* Fail if attempting to use ESL on RHEL-family v5.x, as the dependencies
  for esl-erlang are not available on v5. Blindly continuing leads to a
  broken system - erlang isn't installed, so we fail early with the
  informative log message.
* Don't actually add the erlang solutions yum repo in the "normal"
  package recipe, as that may lead to the wrong erlang package - the
  intention of the recipe is to use EPEL
* On RHEL-family v5 in the package recipe, we need to disable SSL
  verification because the repository used redirects to HTTPS, and
  there's an underlying bug in the redirect code for yum that causes the
  certificate to not be verifiable, even though it is valid.

Fixes #28, might fix #9