common,gpg,kbx: Factor out open_stream_nc.
* common/sysutils.h (open_stream_nc): New. * common/sysutils.c (open_stream_nc): New. * g10/decrypt.c (decrypt_message_fd): Use open_stream_nc. * g10/server.c (cmd_verify): Likewise. * kbx/kbxserver.c (prepare_outstream): Likewise.
- GnuPG-bug-id: T6580
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>