[Nix-dev] download-from-binary-cache.pl: still waiting for ... is chewing time.

[stewart mackenzie]

This is quite annoying, I'm waiting about 30 seconds or more each time
I want to recompile the project and the network is flaky. Is there a
way to disable this cache.nixos.org/<hash>.narinfo seek?

```
$ nix-build --argstr debug true --argstr subnet example_wrangle
download-from-binary-cache.pl: still waiting for
‘https://cache.nixos.org/zh0gxqk936a7cw0kcfn96ny9cy6ccv2g.narinfo’
after 5 seconds...
download-from-binary-cache.pl: still waiting for
‘https://cache.nixos.org/csxcfgvjdxvbhapdyn0fmbpcfxhza0k1.narinfo’
after 5 seconds...
download-from-binary-cache.pl: still waiting for
‘https://cache.nixos.org/qgn83b8n256f3smy41zi1wrb8x5rjzjz.narinfo’
after 5 seconds...
these derivations will be built:
  /nix/store/6dx1w352pi3p0qc6i8rv8fmqksmlrk2y-fs_dir_list.drv
  /nix/store/7l7dwfb0zmcmssp3q32yd8k5456ihkq5-example_wrangle.drv
  /nix/store/97r16a6kxnlrlqj75xcqr9ffiga2vpqw-example_wrangle.drv
  /nix/store/rjxgfx3a4nhcqp9fy4jill51djry8cbi-example_wrangle.drv
building path(s) ‘/nix/store/qgn83b8n256f3smy41zi1wrb8x5rjzjz-fs_dir_list’
unpacking sources
```

/sjm