Only show packages as upgradable if the have a CandidateVer != 0

Closes: #753297

apt-private/private-output.cc

@@ -118,7 +118,7 @@ static std::string GetFlagsStr(pkgCacheFile &CacheFile, pkgCache::PkgIterator P)
    std::string flags_str;
    if (state.NowBroken())
       flags_str = "B";
-   if (P.CurrentVer() && state.Upgradable())
+   if (P.CurrentVer() && state.Upgradable() && state.CandidateVer != NULL)
       flags_str = "g";
    else if (P.CurrentVer() != NULL)
       flags_str = "i";
@@ -229,7 +229,8 @@ void ListSingleVersion(pkgCacheFile &CacheFile, pkgRecords &records,	/*{{{*/
       std::string CandidateVerStr = GetCandidateVersion(CacheFile, P);
       std::string InstalledVerStr = GetInstalledVersion(CacheFile, P);
       std::string StatusStr;
-      if(P.CurrentVer() == V && state.Upgradable()) {
+      if(P.CurrentVer() == V && state.Upgradable() && state.CandidateVer != NULL)
+      {
          strprintf(StatusStr, _("[installed,upgradable to: %s]"),
                    CandidateVerStr.c_str());
       } else if (P.CurrentVer() == V) {

apt-private/private-update.cc

@@ -83,7 +83,7 @@ bool DoUpdate(CommandLine &CmdL)
       for (pkgCache::PkgIterator I = Cache->PkgBegin(); I.end() != true; ++I)
       {
          pkgDepCache::StateCache &state = Cache[I];
-         if (I->CurrentVer != 0 && state.Upgradable())
+         if (I->CurrentVer != 0 && state.Upgradable() && state.CandidateVer != NULL)
             upgradable++;
       }
       const char *msg = P_(