Remove obsolete descriptions for MacOSX

Erlang and V8 is provided through cbdeps

Change-Id: Iaefdc5758b06173c42587a924aac0f8c0796e479
Reviewed-on: http://review.couchbase.org/44513
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>