update model.config example

model.config

@@ -3,9 +3,9 @@
 
 [configs]
 ; If exists 'models' section, this section will be global variable to sub models
+; Otherwise this is the model's config and must be put in the same dirs with model.pb
 TF_INPUT_NODE=input
 TF_OUTPUT_NODE=output
-TF_MODEL_FILE_PATH=path/to/tf_model_opt.pb
 MODEL_TAG=mobile_net
 INPUT_SHAPE=1,64,64,3
 OUTPUT_SHAPE=1,64,64,2