g10: Fix crash.
* g10/getkey.c (get_best_pubkey_byname): If 'get_pubkey_byname' does not return a getkey context, then it can return at most one key, therefore there is nothing to rank. Also, always initialize '*retctx' to be on the safe side.
Fixes: ab89164be02012f1bf159c971853b8610e966301
- GnuPG-bug-id: T2828
- Signed-off-by: Justus Winter <justus@g10code.com>