minor code cleanup. no bug. r/sr=bienvenu

mailnews/base/src/nsMsgMailSession.cpp

@@ -67,8 +67,7 @@ NS_INTERFACE_MAP_END_THREADSAFE
   
 static NS_DEFINE_CID(kMsgAccountManagerCID, NS_MSGACCOUNTMANAGER_CID);
 
-nsMsgMailSession::nsMsgMailSession():
-  mRefCnt(0)
+nsMsgMailSession::nsMsgMailSession()
 {
 
 	NS_INIT_REFCNT();

mailnews/base/src/nsUrlListenerManager.cpp

@@ -40,7 +40,6 @@
 #include "nsUrlListenerManager.h"
 
 nsUrlListenerManager::nsUrlListenerManager() :
-    mRefCnt(0),
     m_listeners(nsnull)
 {
 	NS_INIT_REFCNT();

mailnews/compose/src/nsMsgComposeService.cpp

@@ -141,7 +141,6 @@ nsMsgComposeService::nsMsgComposeService()
   mCachedWindows = nsnull;
 }
 
-/* the following macro actually implement addref, release and query interface for our component. */
 NS_IMPL_ISUPPORTS4(nsMsgComposeService, nsIMsgComposeService, nsIObserver, nsICmdLineHandler, nsISupportsWeakReference);
 
 nsMsgComposeService::~nsMsgComposeService()