IPA: make version check more precise
    
    The call protected by the check does not only expect the version 1 of
    the extdom plugin is used but a specific response type as well. Since
    version 1 can return older response types as well we want to be on the
    safe side.
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    (cherry picked from commit 2fc12875f7d51248799016c19c1298b85e06a286)