http://bugs.winehq.org/show_bug.cgi?id=18997
--- Comment #6 from Florian florian@fkoeberle.de 2009-08-07 09:42:10 --- Do you had another reason for your patch then fixing this bug?
As you might know I tried to submit a similar patch, but got told that returning NULL is a bad idea: http://www.winehq.org/pipermail/wine-devel/2009-March/074267.html I intended then to write a updated patch: http://www.winehq.org/pipermail/wine-devel/2009-March/074277.html but another response coming a few minutes later convinced me to do more research: http://www.winehq.org/pipermail/wine-devel/2009-March/074278.html
As far as I remember returning NULL in schan_free_handle didn't solve the problem completely, but just reduced the chance that you get a crash every minute.
Maybe your second change does make the difference, but I can't test right now if it does. It may take weeks until I can access a PC again which can run Warcraft 3.