fix for bug #98037. sometimes newsgroups would be marked as all read.

bad call to CleanupNewsgroupList(), which calls FinishXOVERLINE()
which adjusts the unread set.  r=mscott, sr=bienvenu

mailnews/news/src/nsNNTPProtocol.cpp

@@ -3355,7 +3355,6 @@ PRInt32 nsNNTPProtocol::BeginReadXover()
 		   &m_firstPossibleArticle, 
 		   &m_lastPossibleArticle);
 
-    CleanupNewsgroupList();
     m_newsgroupList = do_CreateInstance(NS_NNTPNEWSGROUPLIST_CONTRACTID, &rv);
     if (NS_FAILED(rv)) return -1;