DEP: replace the deprecated Thread.isAlive() with .is_alive()

Author: dragonyanglong

src/diffpy/pdfgui/control/fitting.py

@@ -553,7 +553,7 @@ def isThreadRunning(self):
 
         return: True if running, False otherwise
         """
-        return self.thread is not None and self.thread.isAlive()
+        return self.thread is not None and self.thread.is_alive()
 
     def join(self):
         """wait for current fitting to finish"""

src/diffpy/pdfgui/control/pdfguicontrol.py

@@ -159,7 +159,7 @@ def exit(self):
         """exit when program finished
         """
         self.close()
-        if self.queueManager.isAlive():
+        if self.queueManager.is_alive():
             self.queueManager.running = False
 
     def newFitting(self, name, position=None):