partedit: properly handle the scenario where there is no filename

Closes: #111

Author: davvid

src/tools/partedit.py

@@ -1083,8 +1083,7 @@ def addAttributeSlot(self):
     #--------------------------------------------------------------------------
     def dataDirtiedSlot(self, dirty):
         """ Sets the window title with or without "*" for dirty state """
-
-        title = self.data.filename
+        title = self.data.filename or ''
         if dirty:
             title += '*'
         self.setWindowTitle(title)