Protect error counter against overflow.
* util/logger.c (log_inc_errorcount): Protect against overflow. (g10_log_warning): Bumb error counter using the above function. (g10_log_error): Ditto.
This is a similar patch we use in 2.2 and libgpg-error.
- Signed-off-by: Werner Koch <wk@gnupg.org>