nix doctor: no output

[davidak]

Describe the bug

When i run nix doctor i get no output.

Related to #3084 #3102

Steps To Reproduce

1. nix run nixos-unstable.nix
2. nix doctor

Expected behavior

Get the promised log output of the checks results.

I get that with -v:

[davidak@nixos:~]$ nix doctor -v
Running checks against store uri: daemon
[FAIL] Multiple versions of nix found in PATH:
  /nix/store/7fgvivmrhmimsba56p72sssn5qsdw00d-nix-2.3.16/bin
  /nix/store/h538v75x5xgwzy31s5ia3ah7k6cdyzmy-nix-2.7.0/bin

[PASS] All profiles are gcroots.
[FAIL] Warning: protocol version of this client does not match the store.
While this is not necessarily a problem it's recommended to keep the client in
sync with the daemon.

Client protocol: 1.33
Store protocol: 1.21

nix-env --version output

nix (Nix) 2.7.0