fix warning, add a comment. piggybacking on our carpool.

r/sr=no one

mailnews/base/src/nsMsgFolderDataSource.cpp

@@ -939,7 +939,7 @@ nsMsgFolderDataSource::OnItemPropertyFlagChanged(nsISupports *item,
                                                  PRUint32 oldFlag,
                                                  PRUint32 newFlag)
 {
-  nsresult rv;
+  nsresult rv = NS_OK;
 
   if (kBiffStateAtom == property) {
     // for Incoming biff (to turn it on) the item is of type nsIFolder (see nsMsgFolder::SetBiffState)

mailnews/compose/src/nsMsgQuote.cpp

@@ -202,6 +202,8 @@ nsMsgQuote::QuoteMessage(const char *msgURI, PRBool quoteHeaders, nsIStreamListe
   nsCOMPtr <nsIMsgMailNewsUrl> mailNewsUrl = do_QueryInterface(aURL, &rv);
   NS_ENSURE_SUCCESS(rv,rv);
 
+  // SetQuery is safe to use here, as the msgURI that we used for SetSpec()
+  // does not already have a query.
   if (! bAutoQuote) /* We don't need to quote the message body but we still need to extract the headers */
     rv = mailNewsUrl->SetQuery("header=only");
   else if (quoteHeaders)