MyBS: Avoid lock recursion in certificate check
    
    SUSE::MyBS::new tries to fix up API connection error by setting the SUSE
    CA certificate as the SSL trust root.
    
    Check that the error is caused by bad certificate, and don't handle
    other errors so that users can see authentication errors correctly.
    
    Also unlock the cookie storage in case the problem is resolved with
    using the built-in certificate.
    
    Signed-off-by: Michal Suchanek <msuchanek@suse.de>