nghttp2 1.40.0 revert to 1.39.2
nghttp2 1.40.0 revert to 1.39.2

An nghttp2 update broke the build with no trivial way to fix it
in dependent projects.

Ref: https://github.com/nghttp2/nghttp2/pull/1394

vszakats/harbour-deps,vszakats/harbour-deps