gpg: Fix keyring retrieval.
* g10/keyring.c (keyring_get_keyblock): Avoid O(N^2) append.
(cherry picked from commit a7a043e82555a9da984c6fb01bfec4990d904690)
Gbp-Pq: Topic from-master
Gbp-Pq: Name gpg-Fix-keyring-retrieval.patch
- GnuPG-bug-id: T4592
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>