fix pkgProblemResolver::Scores, thanks to Paul Wise.

Closes: #697577

diff --cc apt-pkg/algorithms.cc
index 8cd9d4c,75e914f..7fcd9f0
--- 1/apt-pkg/algorithms.cc
--- 2/apt-pkg/algorithms.cc
+++ b/apt-pkg/algorithms.cc
@@@ -550,11 -550,11 +550,14 @@@ void pkgProblemResolver::MakeScores(
     unsigned long Size = Cache.Head().PackageCount;
     memset(Scores,0,sizeof(*Scores)*Size);
  
--   // Important Required Standard Optional Extra
++   // Maps to pkgCache::State::VerPriority
++   //   which is "Important Required Standard Optional Extra"
++   // (yes, that is confusing, the order of pkgCache::State::VerPriority
++   //  needs to be adjusted but that requires a ABI break)
     int PrioMap[] = {
        0,
-       _config->FindI("pkgProblemResolver::Scores::Important",3),
-       _config->FindI("pkgProblemResolver::Scores::Required",2),
+       _config->FindI("pkgProblemResolver::Scores::Important",2),
+       _config->FindI("pkgProblemResolver::Scores::Required",3),
        _config->FindI("pkgProblemResolver::Scores::Standard",1),
        _config->FindI("pkgProblemResolver::Scores::Optional",-1),
        _config->FindI("pkgProblemResolver::Scores::Extra",-2)