Merge branch 'master' into core-updates

authenticate: Allow signatures with binary data to be written to stdout.

Fixes <http://bugs.gnu.org/17312>.

* guix/scripts/authenticate.scm (guix-authenticate): Add calls to
  'set-port-encoding!' and 'set-port-conversion-strategy!'.  Wrap body
  in 'with-fluids' form that sets '%default-port-encoding' and
  '%default-port-conversion-strategy'.
* tests/guix-authenticate.sh: Add test.
* tests/pk-crypto.scm ("hash corrupt due to restrictive locale
  encoding"): Add reference to bug.

authenticate: Support reading the hash or key from stdin.

* guix/scripts/authenticate.scm (guix-authenticate): Add clauses
  for ("rsautl" "-sign" "-inkey" key) and ("rsautl" "-verify" "-inkey" _
  "-pubin").
* tests/guix-authenticate.sh (hash): Add test using -sign and -verify in
  a pipeline.

Merge branch 'master' into core-updates

authenticate: Add test.

* tests/guix-authenticate.sh: New file.
* Makefile.am (SH_TESTS): Add it.