Revert "MB-11406: Revert *master* only to Erlang R14, for performance comparisons"

This reverts commit 23e4ec7684eccd11dc3d0c79608c53978b856d13.

Change-Id: I447aff0dadcbf84425d143c6cc351074d8c5de66
Reviewed-on: http://review.couchbase.org/42057
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>