CBIT-532:  move root to 's3://packages.couchbase.com/builds/'

Change-Id: I799059616e58eb79ae762e4f52bbfa44c82599a0
Reviewed-on: http://review.couchbase.org/37286
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>