event: use cPickle for events

(Bitbake rev: b16c0c1dc3b7e03b02555e9803767a0d695e67f1)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/event.py

@@ -24,7 +24,10 @@ BitBake build tools.
 
 import os, sys
 import warnings
-import pickle
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
 import logging
 import atexit
 import bb.utils