commitHash RPC doesn't work on container images.

[sgkim126]

Images in https://hub.docker.com/r/kodebox/codechain/tags don't return commitHash RPC properly.

curl     -H 'Content-Type: application/json'     -d '{"jsonrpc": "2.0", "method": "commitHash", "params": [], "id": null}'     localhost:8080
{"jsonrpc":"2.0","result":"","id":null}

It should return a git hash but an empty string is returned.

I thought that it's the problem of vergen(https://github.com/rustyhorde/vergen) because it uses system installed git binary not the git2 library. rustyhorde/vergen#15
But Dockerfile installs git.

codechain/docker/ubuntu/Dockerfile

Line 10 in c9ec8b3

git \

And I suspected that strip removed the docker hash.

codechain/docker/ubuntu/Dockerfile

Line 37 in c9ec8b3

strip /build/codechain/target/release/codechain

But when I run the binary which is stripped manually, commitHash RPC works fine.