#23 Key merging needs to better process signature packets

[V. Alex Brennen]

If we are merging two keys and the new key material
being submitted contains signatures which modify the
qualities of the public key, known User ID's, or known
subkets the database tables are not updated with the
modifications. For example, a signature packet which
changes the expiration date of the public key will not
updated the expiration date of the public key in the
database.