Make get_inference_program support for Evaluator.

python/paddle/v2/fluid/io.py

@@ -14,6 +14,7 @@
 import os
 import cPickle as pickle
 
+from paddle.v2.fluid.evaluator import Evaluator
 from paddle.v2.fluid.framework import Program, Parameter, default_main_program, Variable
 
 __all__ = [
@@ -183,6 +184,8 @@ def load_persistables(executor, dirname, main_program=None):
 def get_inference_program(target_vars, main_program=None):
     if main_program is None:
         main_program = default_main_program()
+    if isinstance(target_vars, Evaluator):
+        target_vars = target_vars.states + target_vars.metrics
     if not isinstance(target_vars, list):
         target_vars = [target_vars]