Fixed bug 2877: kmail segfaults on startup when ~/Mail does not exist

svn path=/trunk/kdenetwork/kmail/; revision=44497

kmfolder.cpp

@@ -100,7 +100,7 @@ KMFolder :: ~KMFolder()
   /* Well, this is a problem. If I add the above line then kmfolder depends
    * on kmaccount and is then not that portable. Hmm.
    */
-  undoStack->folderDestroyed(this);
+  if (undoStack) undoStack->folderDestroyed(this);
 }
 
 

kmfoldermgr.cpp

@@ -44,7 +44,7 @@ KMFolderMgr::KMFolderMgr(const QString& aBasePath):
 //-----------------------------------------------------------------------------
 KMFolderMgr::~KMFolderMgr()
 {
-  undoStack->clear(); // Speed things up a bit.
+  if (undoStack) undoStack->clear(); // Speed things up a bit.
   mBasePath = QString::null;;
 }