Patch for AqBanking Windows bug 586122

[Geert Janssens]

I have attached a patch to this bug
https://bugzilla.gnome.org/show_bug.cgi?id=586122

I think this patch should solve the bug, but I can't test it myself as I don't 
have access to a Windows environment.

I see two possible options:
* This is a patch for the build scripts. If I commit it, the nightly build can 
be used to test it.
* Someone with access to Windows has a look at it.

Geert