Fixed caching issues

Fixed exception raised during cache reading

Switched cache hashing to hashlib

In python 3.3 the hash function is returning different hashes during
different executions of the application.

jedi/cache.py

@@ -21,6 +21,7 @@ from __future__ import with_statement
 import time
 import os
 import sys
+import hashlib
 try:
     import cPickle as pickle
 except:
@@ -312,7 +313,7 @@ class _ModulePickling(object):
         shutil.rmtree(self._cache_directory())
 
     def _get_hashed_path(self, path):
-        return self._get_path('%s.pkl' % hash(path))
+        return self._get_path('%s.pkl' % hashlib.md5(path.encode("utf-8")).hexdigest())
 
     def _get_path(self, file):
         dir = self._cache_directory()

jedi/parsing_representation.py

@@ -560,7 +560,7 @@ class Flow(Scope):
     @parent.setter
     def parent(self, value):
         self._parent = value
-        if self.next:
+        if hasattr(self, "next") and self.next:
             self.next.parent = value
 
     def get_code(self, first_indent=False, indention='    '):