fix crash when P.Arch() was used but the cache got remapped

diff --combined apt-pkg/acquire-item.cc
index 9313c4b47f7f44dfef3f87233a5085cae762bad3,7eb5920e0c1d4935f0c8a70862d195595f5e1e63..d4b451d5b73c2c0f6afefd01010c54a9f3d6fd31
--- 1/apt-pkg/acquire-item.cc
--- 2/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@@ -1258,7 -1258,7 +1258,7 @@@ void pkgAcqMetaIndex::Done(string Messa
        if (SigFile == "")
        {
           // There was no signature file, so we are finished.  Download
-          // the indexes and do hashsum verification
+          // the indexes and do only hashsum verification
           MetaIndexParser->Load(DestFile);
           QueueIndexes(true);
        }
@@@ -1397,7 -1397,6 +1397,7 @@@ void pkgAcqMetaIndex::QueueIndexes(boo
            {
               std::cerr << "Queueing: " << (*Target)->URI << std::endl;
               std::cerr << "Expected Hash: " << ExpectedIndexHash.toStr() << std::endl;
 +             std::cerr << "For: " << Record->MetaKeyFilename << std::endl;
            }
            if (ExpectedIndexHash.empty() == true && (*Target)->IsOptional() == false)
            {