gpg: Fix edge case in --refresh-keys
* g10/keyserver.c (keyserver_get): Take care of NO_DATA in one chunk.
This should fix this bug:
gnupg fetches the keys in batches (chunks) of, e.g., 21 keys per
batch. If all keys of a single batch of 21 keys do not have a
representation on the key server, gnupg aborts the overall update
process with an error, not fetching all the key updates from the
server.
- GnuPG-bug-id: T8197