Require libgpg-error 1.11.

* configure.ac (NEED_GPG_ERROR_VERSION): Set to 1.11.
* common/util.h: Remove GPG_ERR_ replacements.

The replacement macros actually never worked because gog-error.h uses
enums and not macros. libgpg-error 1.11 is 6 months old and thus it
should not be a problem to require that version.

Future replacement macros may then use the new
GPG_ERROR_VERSION_NUMBER to detect missing error codes.

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