BaseTools mingw-gcc-build.py: Update mingw-w64 source path
BaseTools mingw-gcc-build.py: Update mingw-w64 source path

The old path was removed from the mingw-w64 download files section.


git-svn-id: f3880c1fc5096ce2109c8aec392d8e07f619f417@1979 c2973edb-eda0-4c78-bc6a-9341b269661f

tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools,bitcrystal/buildtools-BaseTools,tianocore/buildtools-BaseTools