When building e.g. nixpkgs, the "Running builds" view will mostly look
like this
hello.x86_64-linux (Build of hello-X.Y)
exa.x86_64-linux (Build of exa-X.Y)
...
This doesn't provide any useful information. Showing the step name only
makes sense if it's not a child of the job's derivation. With this
patch, that information will only be shown if the drv name (i.e. w/o
`/nix/store/` prefix, .drv ext & hash) is not equal to the drv name of
the job itself (build.nixname).
9d8f30affe