bug#23828: unsupported sexp item type #f ```

[David Craven <david@craven.ch>]

Maybe not a bug, but I'm getting the same backtrace when trying to run
./guix archive or ./guix package -i guix or ./guix pull.

Trying to install guix 0.10.0 binary tarball on nixos.

```nix
users.users = {
    guixbuild1 = {
      isSystemUser = true;
      group = "guixbuild";
    };
  };

  users.groups.guixbuild = {};
```

```sh
bin  sudo ./guix archive --authorize < ../share/guix/hydra.gnu.org.pub

/gnu/store/3g6zn8y5sfwywr4pqiwqrab735a0x4zl-guix-0.10.0/bin
warning: failed to install locale: Invalid argument
Backtrace:
In ice-9/boot-9.scm:
 157: 17 [catch #t #<catch-closure 18097a0> ...]
In unknown file:
   ?: 16 [apply-smob/1 #<catch-closure 18097a0>]
In ice-9/boot-9.scm:
  63: 15 [call-with-prompt prompt0 ...]
In ice-9/eval.scm:
 432: 14 [eval # #]
In ice-9/boot-9.scm:
2401: 13 [save-module-excursion #<procedure 1826940 at
ice-9/boot-9.scm:4045:3 ()>]
4050: 12 [#<procedure 1826940 at ice-9/boot-9.scm:4045:3 ()>]
1724: 11 [%start-stack load-stack ...]
1729: 10 [#<procedure 183eea0 ()>]
In unknown file:
   ?: 9 [primitive-load
"/gnu/store/3g6zn8y5sfwywr4pqiwqrab735a0x4zl-guix-0.10.0/bin/.guix-real"]
In guix/ui.scm:
1188: 8 [run-guix-command archive "--authorize"]
In ice-9/boot-9.scm:
 157: 7 [catch srfi-34 #<procedure 276d1c0 at guix/ui.scm:419:2 ()> ...]
 157: 6 [catch system-error ...]
In guix/scripts/archive.scm:
 328: 5 [#<procedure 276c7b0 at guix/scripts/archive.scm:318:2 ()>]
 303: 4 [authorize-key]
In ice-9/boot-9.scm:
 702: 3 [map #<procedure sexp->canonical-sexp (sexp)> (#f)]
In guix/pk-crypto.scm:
 375: 2 [sexp->canonical-sexp #f]
In unknown file:
   ?: 1 [call-with-output-string #<procedure 27704a0 at
guix/pk-crypto.scm:376:5 (port)>]
   ?: 0 [scm-error misc-error #f "~A ~S" ("unsupported sexp item type" #f) #f]

ERROR: In procedure scm-error:
ERROR: unsupported sexp item type #f
```