Try harder to avoid err being undefined in resultsdb_report
    
    Seems Python has a kind of odd behaviour where when you assign
    err in an except block clause like this it actually gets deleted
    deleted once we leave the except block, even when it was declared
    at a wider scope earlier (as here). This solves that problem by
    using a temporary variable to assign the exception to.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>