common: Avoid warning about implicit declaration of gnupg_fd_valid.

common: Avoid warning about implicit declaration of gnupg_fd_valid.

* common/logging.c: Add #include "sysutils.h".

--

Without this, we see:

logging.c:573:9: warning: implicit declaration of function \
  ‘gnupg_fd_valid’ [-Wimplicit-function-declaration]
   if (! gnupg_fd_valid (fd))
         ^~~~~~~~~~~~~~

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
(cherry picked from commit 8810314e377a9cb6612150a57cf99260ed0bb9f6)

Gbp-Pq: Name 0033-common-Avoid-warning-about-implicit-declaration-of-g.patch