bullet proofing for crasher bug #194335.

some additional code clean up (found while reviewing bug #190106.
r/sr=bienvenu

mailnews/imap/src/nsImapProtocol.cpp

@@ -1405,8 +1405,8 @@ PRBool nsImapProtocol::ProcessCurrentURL()
     if (m_channelListener) 
     {
         nsCOMPtr<nsIRequest> request = do_QueryInterface(m_mockChannel);
-        if (!request) return NS_ERROR_FAILURE;
-
+        NS_ASSERTION(request, "no request");
+        if (request)
           rv = m_channelListener->OnStopRequest(request, m_channelContext, NS_OK);
     }
   m_lastActiveTime = PR_Now(); // ** jt -- is this the best place for time stamp
@@ -5658,6 +5658,8 @@ PRBool nsImapProtocol::MailboxIsNoSelectMailbox(const char *mailboxName)
   if (!name)
     return PR_FALSE;
 
+  NS_ASSERTION(m_imapServerSink, "unexpected, no imap server sink, see bug #194335");
+  if (m_imapServerSink)
     m_imapServerSink->FolderIsNoSelect(name, &rv);
 
   PL_strfree(name);