Upgrade to winstone 5.15
Upgrade to winstone 5.15

Signed-off-by: olivier lamy <d3548cf353cfa8a03c6f2a815e39e2c0a78449a5@apache.org>

DanielWeber/jenkins,DanielWeber/jenkins,DanielWeber/jenkins,DanielWeber/jenkins,DanielWeber/jenkins,DanielWeber/jenkins,DanielWeber/jenkins