win32: fix incorrect specifier
win32: fix incorrect specifier

error: format ‘%u’ expects argument of type ‘unsigned int’, but argument 4 has
   type ‘gsize {aka long long unsigned int}’ [-Werror=format=]

https://bugzilla.gnome.org/show_bug.cgi?id=755154

cention-sany/glib,MathieuDuponchelle/glib,Distrotech/glib,endlessm/glib,mzabaluev/glib,ieei/glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,Distrotech/glib,cention-sany/glib,mzabaluev/glib,Distrotech/glib,cention-sany/glib,MathieuDuponchelle/glib,ieei/glib,endlessm/glib,johne53/MB3Glib,ieei/glib,cention-sany/glib,johne53/MB3Glib,MathieuDuponchelle/glib,ieei/glib,johne53/MB3Glib,johne53/MB3Glib,MathieuDuponchelle/glib,cention-sany/glib,tchakabam/glib,tchakabam/glib,tchakabam/glib,Distrotech/glib,johne53/MB3Glib,tchakabam/glib,mzabaluev/glib,Distrotech/glib,endlessm/glib,MathieuDuponchelle/glib,mzabaluev/glib,tchakabam/glib,ieei/glib,mzabaluev/glib