tests: Fix distcheck.
tests: Fix distcheck.

* tests/start-stop-agent: Do not create 'gpg-agent.conf' if it does
not exist.

Fixes-commit: 16b202d9999591b71fb8bb49f6db10ef96d4cbe8
Signed-off-by: Justus Winter <4d1bd7a5ca1cd26bee0df05b6801a6ce9a22196e@g10code.com>

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme