CBD-1463: Update erlang to R16B03-cb2 for OS X

R16B03-cb2 runs Erlang's Install script after extracting, which sets
the correct path for erlang's ROOTDIR.

Change-Id: Ibb7b41af2f9171b86a6ffecd9d0b84ccfd1a9beb
Reviewed-on: http://review.couchbase.org/43645
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>