DependsPolicy: print some info when skipping the dep check
The autopkgtest policy prints when it doesn't run a test due to a
package being unsatisfiable on an arch. This can be a bit mysterious,
and it can seem like it's causing the package to not become a candidate,
when it's not. Print some info when we decide not to skip indicating
what happened.
- Binary in target taken over by new source
- Not cleaned up yet
- New source updated in source suite
We can have *three* copies of a source package visible to britney at
once. Handle this case by recording the source package a pkgid was seen
in before.
On some distros (Ubuntu), arch:all packages are built along with one of
the architectures. We shouldn't be listing 'all' as its own arch in this
case. Instead we filter out the binaries except for on the
'all_buildarch'.
