Confusing wrong Autocrypt error message

Under the following conditions

• Balsa is compiled with Autocrypt support,
• no identity has Autocrypt enabled,
• a new GnuPG signed message for which the public key is not present in the key ring is received, and
• the message includes a valid Autocrypt: header

Balsa emits the (wrong) message

The message contains an Autocrypt header, but it is either broken
or the signature has been created using a different key.

In detail, the following happens:

1. libbalsa_message_headers_from_gmime() remembers that the message includes a valid Autocrypt: header;
2. balsa_message_set() calls autocrypt_from_message() iff the message is new and at least one identity has Autocrypt support enabled. This function imports the information from the Autocrypt: header into the Autocrypt database;
3. balsa_mime_widget_signature_widget() tries to read Autocrypt information from the database which is not present as autocrypt_from_message() has not been called in the previous step. But as in step 1 the header has been detected, it emits the confusing error message.

IMHO, we have two options:

• either we just remove the check in step 2., i.e. we always import Autocrypt data into the database, even if no identity is configured to use it, or
• in step 3. we simply suppress the message if no identity uses Autocrypt.

I am inclined to implement the first solution, as this would still offer to import the key extracted from the Autocrypt: header into the database and would warn if the header is really broken (and it's easier – just remove a few lines of code…).

Opinions?