Remove out of date 1password.keys file from DB

The 1password.keys file is currently not written by
the client, only encryptionKeys.js is maintained so this file
is out of date.

Remove it for the moment.
Fix error being swallowed if import failed due to file not being found
Fix error when copying item fields if item has field values with an empty designation attribute

If fields have been saved other than the username and password
fields then they will have a null designation.