Converted sessions tests from doctest to unittest.

Also made the FileSession backend consistent with other backends in one
corner case uncovered by the conversion, namely that the backend should
create a new key if the one passed in is invalid.



git-svn-id: http://code.djangoproject.com/svn/django/trunk@13482 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/sessions/backends/file.py

@@ -58,7 +58,7 @@ class SessionStore(SessionBase):
             finally:
                 session_file.close()
         except IOError:
-            pass
+            self.create()
         return session_data
 
     def create(self):