update comment

doc/faq.txt

@@ -67,7 +67,8 @@ should reoptimize its graph or not. Theano users can use the standard python pic
 tools to save a compiled theano function. When pickling, both graph before and 
 after the optimization are saved, including shared variables. When set to True, 
 the graph is reoptimized when being unpickled. Otherwise, skip the graph optimization 
-and use directly the optimized graph from the pickled file.
+and use directly the optimized graph from the pickled file. After Theano 0.7,
+the default changed to False.
 
 Faster Theano function
 ----------------------