Remove support for the GPG_AGENT_INFO envvar.

* agent/agent.h (opt): Remove field use_standard_socket.
* agent/command.c (cmd_killagent): Always allow killing.
* agent/gpg-agent.c (main): Turn --{no,}use-standard-socket and
--write-env-file into dummy options.  Always return true for
--use-standard-socket-p. Do not print the GPG_AGENT_INFO envvar
setting or set that envvar.
(create_socket_name): Simplify by removing non standard socket
support.
(check_for_running_agent): Ditto.
* common/asshelp.c (start_new_gpg_agent): Remove GPG_AGENT_INFO use.
* common/simple-pwquery.c (agent_open): Ditto.
* configure.ac (GPG_AGENT_INFO_NAME): Remove.
* g10/server.c (gpg_server): Do not print the AgentInfo comment.
* g13/server.c (g13_server): Ditto.
* sm/server.c (gpgsm_server): Ditto.
* tools/gpgconf.c (main): Simplify by removing non standard socket
support.
--

The indented fix to allow using a different socket than the one in the
gnupg home directory is to change Libassuan to check whether the
socket files exists as a regualr file with a special keyword to
redirect to another socket file name.
po: Update German translation.
po: Auto update translations.

--
gpg: Check gpg-agent version before 2.1 migration.

* g10/call-agent.c, g10/call-agent.h (agent_get_version): New.
* g10/migrate.c (migrate_secring): Abort migration if
agent_get_version returns not at least 2.1.0

--
GnuPG-bug-id: 1718

On the first installation of GnuPG 2.1 it is likely that an
old gpg-agent is still running in the environment. In that
case the migration would fail.

Signed-off-by: Andre Heinecke <aheinecke@intevation.de>
build: Add configure options --disable-{ntb,gnu}tls.

* configure.ac: Add --disable-ntbtls and --disable-gnutls.
Some doc fixes and a fix for "make distcheck".

--
gpg: Allow creating a cert-only primary key.

* g10/keygen.c (ask_key_flags): Allow a 'c' in direct entry.
--

GnuPG-bug-id: 1726
speedo: Add INSTALL_PREFIX feature.

--

With this it is now possible build and install gnupg 2.1 properly
below /usr/local:

  make -f TOPSRC/build-aux/speed.ml native INSTALL_PREFIX=/usr/local

Of course you need installation priviliges for the /usr/local tree.
Release 2.1.0-beta864.
doc: Minor fix.

--

Due to todays reminder:

  On Tue 2014-04-22 18:46:15 -0400, Daniel Kahn Gillmor wrote:
  > With --trust-model=always, all keys and user IDs are considered
  > automatically valid; they are not automatically trusted (setting
  > universal ownertrust to anything other than "ultimate" would be
  > insufficient to acheive the effect of --trust-model=always, due to
  > --max-cert-depth and certificate path reachability).
  >
  > Thanks to Nicolai Josuttis for pointing out this documentation
  error.