- Execute the SQL in the same way as everywhere else.
- Note: the comment that the keydata was not being deleted was
inaccurate: the "ON DELETE CASCADE"s ensures that the key and all
associated data is removed from the database.
- When creating a new key, quote the name part of the User ID. This
is essential to support names with @ characters and commas, which
are often used by pEp.
- More carefully extract URIs from User IDs.
- Don't forget to extract them in email_cmp.