remove MTU varible, and use the default value:1500

Issue-ID: APPC-384
Change-Id: If4573bed08b1b8d01f5eadc3da0d5f66aa044e07
Signed-off-by: Taka <tc012c@att.com>
diff --git a/docker-compose/docker-compose.yml b/docker-compose/docker-compose.yml
index d7d1665..5b60385 100644
--- a/docker-compose/docker-compose.yml
+++ b/docker-compose/docker-compose.yml
@@ -3,8 +3,6 @@
 networks:
   default:
     driver: bridge
-    driver_opts:
-      com.docker.network.driver.mtu: ${MTU}
 
 services:
   db: