...

src/calibre/ptempfile.py

@@ -46,7 +46,10 @@ def __exit__(self, *args):
         self.close()
 
     def __del__(self):
-        self.close()
+        try:
+            self.close()
+        except:
+            pass
 
 
 def PersistentTemporaryDirectory(suffix='', prefix='', dir=None):

src/calibre/utils/osx_symlinks.py

@@ -7,6 +7,7 @@
 __docformat__ = 'restructuredtext en'
 
 import sys, os, cPickle
+from calibre.constants import isnewosx
 
 AUTHTOOL="""#!/usr/bin/python
 import os
@@ -27,7 +28,7 @@
 DEST_PATH = '/usr/bin'
 
 def create_symlinks():
-    return create_symlinks_new() if getattr(sys, 'new_app_bundle', False) else create_symlinks_old()
+    return create_symlinks_new() if isnewosx else create_symlinks_old()
 
 def get_scripts():
     return cPickle.load(open(P('scripts.pickle'), 'rb'))