Merge pull request ApolloAuto#32 from fengqikai1414/master

fix AttributeError when writing a new pb msg to rosbag

Author: quning18

ros/ros_comm/rosbag/src/rosbag/bag.py

@@ -349,7 +349,7 @@ def write(self, topic, msg, t=None, raw=False):
                 header = { 'topic' : topic, 'type' : msg_type, 'md5sum' : md5sum, 'message_definition' : pytype._full_text }
             else:
                 if issubclass(msg.__class__, google.protobuf.message.Message):
-                    roslib.message.add_rosmsg_interface_for_protobuf(msgsg.__class__)
+                    roslib.message.add_rosmsg_interface_for_protobuf(msg.__class__)
                     header = { 'topic' : topic, 'type' : msg.__class__._type, 'md5sum' : msg.__class__._md5sum, 'message_definition' : 'protobuf' }
                 else:
                     header = { 'topic' : topic, 'type' : msg.__class__._type, 'md5sum' : msg.__class__._md5sum, 'message_definition' : msg._full_text }