don't try to get acquire lock in simulation mode

The code moving in eb1f04dda07c2b69549ad9fd793cca0e91841b3e
moved the acquire stuff above the simulation exit, so before getting
locks (and creating/chmod directories) we should be checking if we
should actually really do it…

[ignore as bugfix of an unreleased commit]

Git-Dch: Ignore

apt-private/private-install.cc

@@ -111,6 +111,8 @@ bool InstallPackages(CacheFile &Cache,bool ShwKept,bool Ask, bool Safety)
       // force a hashsum for compatibility reasons
       _config->CndSet("Acquire::ForceHash", "md5sum");
    }
+   else if (_config->FindB("APT::Get::Simulate") == true)
+      ;
    else if (Fetcher.GetLock(_config->FindDir("Dir::Cache::Archives")) == false)
       return false;