Fix warning when running IPython.kernel tests

The signature of TemporaryDirectory.cleanup() changed just before Python 3.2, and our
TemporaryWorkingDirectory subclass was receiving an unexpected parameter. This copies
in a newer TemporaryDirectory.cleanup() implementation for Python 2.7.

IPython/utils/tempdir.py

@@ -32,15 +32,30 b' except ImportError:'
         def __enter__(self):
             return self.name
 
-        def cleanup(self):
-            if not self._closed:
+        def cleanup(self, _warn=False):
+            if self.name and not self._closed:
+                try:
                 self._rmtree(self.name)
+                except (TypeError, AttributeError) as ex:
+                    # Issue #10188: Emit a warning on stderr
+                    # if the directory could not be cleaned
+                    # up due to missing globals
+                    if "None" not in str(ex):
+                        raise
+                    print("ERROR: {!r} while cleaning up {!r}".format(ex, self,),
+                          file=_sys.stderr)
+                    return
                 self._closed = True
+                if _warn:
+                    self._warn("Implicitly cleaning up {!r}".format(self),
+                               ResourceWarning)
 
         def __exit__(self, exc, value, tb):
             self.cleanup()
 
-        __del__ = cleanup
+        def __del__(self):
+            # Issue a ResourceWarning if implicit cleanup needed
+            self.cleanup(_warn=True)
 
 
         # XXX (ncoghlan): The following code attempts to make
@@ -124,9 +139,9 b' class TemporaryWorkingDirectory(TemporaryDirectory):'
         _os.chdir(self.name)
 
 
-    def cleanup(self):
+    def cleanup(self, _warn=False):
         #Revert to old cwd.
         _os.chdir(self.old_wd)
 
         #Cleanup
-        super(TemporaryWorkingDirectory, self).cleanup()
+        super(TemporaryWorkingDirectory, self).cleanup(_warn=_warn)