g10/mainproc: avoid extra hash contexts when decrypting AEAD input
* g10/mainproc.c (mainproc_context): New member 'seen_pkt_encrypted_aead'. (release_list): Clear 'seen_pkt_encrypted_aead'. (proc_encrypted): Set 'seen_pkt_encrypted_aead'. (have_seen_pkt_encrypted_aead): New. (proc_plaintext): Do not enable extra hash contexts when decryption AEAD input.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>