common: Fix buffer copy code again.
* common/exectool.c (my_error_from_errno): Remove. (copy_buffer_do_copy): Do without var RC. (copy_buffer_flush): Ditto. Use ERRNO instead of es_write return code. (gnupg_exec_tool): Correctly return errors from es_read.
- Fixes-commit: 55c9212a2338bf0b07c8cf3a69bcedaa28d48d43
- Signed-off-by: Werner Koch <wk@gnupg.org>