g10: Implement gpg --quick-revuid

* g10/revoke.c (get_default_uid_revocation_reason): New.
* g10/keyedit.c (menu_revuid): Break out creation of uid revocation
into new function core_revuid.
* g10/keyedit.c (keyedit_quick_revuid): New. Selects key and
uid, invokes core_revuid.
* g10/gpg.c (main): Handle --quick-revuid argument.
* doc/gpg.texi: Document --quick-revuid.

--

This functionality is a counterpart to --quick-adduid, and will be
useful for projects that depend programmatically on gpg to revoke user
IDs (one such example is "monkeysphere-host revoke-servicename").

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>

- Minor re-indentation work.
- Changed a "0 == memcmp" to "!memcmp"
- Removed tests/openpgp/quick-key-manipulation.test from the
  Makefile.  This test needs to be converted to gpgscm.
- Removed example from whats-new-in-2.1.txt because that is generated.

Signed-off-by: Werner Koch <wk@gnupg.org>

doc/gpg.texi

@@ -1041,6 +1041,15 @@ the interactive sub-command @code{adduid} of @option{--edit-key} the
 white space removed, it is expected to be UTF-8 encoded, and no checks
 on its form are applied.
 
+@item --quick-revuid  @var{user-id} @var{user-id-to-revoke}
+@opindex quick-revuid
+This command revokes a User ID on an existing key.  It cannot be used
+to revoke the last User ID on key (some non-revoked User ID must
+remain), with revocation reason ``User ID is no longer valid''.  If
+you want to specify a different revocation reason, or to supply
+supplementary revocation text, you should use the interactive
+sub-command @code{revuid} of @option{--edit-key}.
+
 @item --passwd @var{user_id}
 @opindex passwd
 Change the passphrase of the secret key belonging to the certificate