!9177 [ModelZoo]Change gcn early_stop epoch

From: @zhan_ke
Reviewed-by: @oacjiewen,@yingjy
Signed-off-by: @yingjy

model_zoo/official/gnn/gcn/src/config.py

@@ -23,4 +23,4 @@ class ConfigGCN():
     hidden1 = 16
     dropout = 0.5
     weight_decay = 5e-4
-    early_stopping = 10
+    early_stopping = 50