Ignore dependencies of cruft when building excuses.

Don't make dependencies of cruft a blocker for being a candidate. In most cases, the cruft won't migrate to testing, so it shouldn't be a blocker. If the cruft would be considered for migration to testing, the installability check will catch missing deps.

Passes all the tests in the testsuite (and makes the test of this case pass).

In the live-data set, passes all the test. In live-2016-04-11, more packages migrate, because gdcm (plus rdeps) was blocked by the cruft libgdcm2.4 dependency on an old libssl1.0.0, which was no longer in testing.

Signed-off-by: Ivo De Decker ivodd@debian.org