Fix build on mingw32 by disabling netcf

* autobuild.sh, mingw32-libvirt.spec.in: Set --without-netcf for
  mingw32 builds

autobuild.sh

@@ -79,6 +79,7 @@ if [ -x /usr/bin/i686-pc-mingw32-gcc ]; then
     --without-one \
     --without-phyp \
     --without-esx \
+    --without-netcf \
     --without-libvirtd
 
   make

mingw32-libvirt.spec.in

@@ -55,6 +55,7 @@ MinGW Windows libvirt virtualization library.
   --without-one \
   --without-phyp \
   --without-esx \
+  --without-netcf \
   --without-libvirtd
 make