Bug#860108: Handle removal of architectures from releases while building versions.idx

Package: debbugs
Severity: normal

 perl ../bin/dump_db.pl versions.idx autodocktools|grep -C 4 testing
[...]
            'testing' => {
                           'powerpc' => [
                                          '1.5.7-1'
                                        ]
                         }

The removal of an entire arch, like powerpc from testing leaves package
versions behind. Catch this more elegantly while building versions.idx.

--
Don Armstrong                      https://www.donarmstrong.com

Where I sleep at night, is this important compared to what I read
during the day? What do you think defines me? Where I slept or what I
did all day?
 -- Thomas Van Orden of Van Orden v. Perry