Revert 3.0.0 builds to Erlang R14 for Linux and Mac (hopefully temporarily)

Change-Id: I215641250f45e9b08e6c44f0afef7ce4dafe0cbf
Reviewed-on: http://review.couchbase.org/36694
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>