ipaserver/dcerpc: unify error processing
    
    Samba error code reporting changes from version to version but we also
    did not provide proper input into DCE RPC error processing method we
    have.
    
    Unify error processing and add few more fallback entries.
    
    With Samba 4.7 we'll have to change it again because error code
    processing for Samba Python modules will change with introduction of
    samba.ntstatus and samba.werror modules.
    
    Note that this commit also changes a message returned for error code
    -1073741772 (NT_STATUS_OBJECT_NOT_FOUND) because it is more general one.
    
    Fixes https://pagure.io/freeipa/issue/6859
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>