Use gem version of rest-client

ssl_version was added in a forked version in 2012
It was later moved into its own git repo

The implementation changed of ssl_version but is
similar enough for our needs

https://github.com/L2G/rest-client-fork/issues/3 (we applied #123 and a few more tweaks)
# 1.6.7 applied #140, but later removed and added to the 1.7.0 branch due to default v3 issues with some servers
# https://github.com/ManageIQ/rest-client/commit/0354d26b2082e1278342bab6c73b88891187f8fa