keyserver: Allow use of cURL's default CA store.
* keyserver/gpgkeys_curl.c (main): Set CURLOPT_CAINFO only if a file has been given. * keyserver/gpgkeys_hkp.c (main): Ditto.
(cherry picked from commit e957b9b3f408491f36660499b215aebcf2633a95)
- GnuPG-bug-id: T1542
- Signed-off-by: Werner Koch <wk@gnupg.org>