drop incorrect parameter implicitely converted to bool

The helper expects to be told if it should generate messages, not where
these messages should be printed – as it isn't printing such messages,
but puts them in _error. apt-get uses in other methods a helper
specialisation which does also print stuff to a stream through, so this
is likely a copy&paste error.

Git-Dch: Ignore

cmdline/apt-get.cc

@@ -617,7 +617,7 @@ static bool DoDownload(CommandLine &CmdL)
    if (Cache.ReadOnlyOpen() == false)
       return false;
 
-   APT::CacheSetHelper helper(c0out);
+   APT::CacheSetHelper helper;
    APT::VersionSet verset = APT::VersionSet::FromCommandLine(Cache,
 		CmdL.FileList + 1, APT::CacheSetHelper::CANDIDATE, helper);
 
@@ -1534,7 +1534,7 @@ static bool DoChangelog(CommandLine &CmdL)
    if (Cache.ReadOnlyOpen() == false)
       return false;
    
-   APT::CacheSetHelper helper(c0out);
+   APT::CacheSetHelper helper;
    APT::VersionList verset = APT::VersionList::FromCommandLine(Cache,
 		CmdL.FileList + 1, APT::CacheSetHelper::CANDIDATE, helper);
    if (verset.empty() == true)