169c6b4b14
Make the revision metadata constant, in order to avoid needless retesting. The human version (e.g. 21.05-pre) is left as is, because it is useful for external modules that test with e.g. nixosTest and rely on that version number.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at https://nixos.org/nixos and in the manual in doc/manual.