1175818 - Fix failure on Errata with missing "sum"

https://bugzilla.redhat.com/show_bug.cgi?id=1175818
On 12/19/2014 02:39 PM, Jeff Ortel wrote:
> Shouldn't this contain a 'sum': None.
> Seems we should be testing {'sum': None} and {}. /sum missing/
> Or, am I missing something?

This data structure actually does have the sums set to None. The newly
introduces SUMLESS_ERRATA below this is the one that doesn't have the
sum attribute. Both scenarios are tested in the TestMigrateErrata class
below.