sync.profile: Point to qtsystems#dev

qtconnectivity doesn't really depend on qtsystems, so
this is a temporary solution until qt5.git#qt.pro is
updated.

Change-Id: I89811ccc82d5cc46503ab270f4d50423b3313c60
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>