CBLT-252:  only upload artifacts and zip files if unit tests pass

Change-Id: Iad20e530aae1f8da9adec2732d982fdc2ac15a00
Reviewed-on: http://review.couchbase.org/35509
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>