Add mtu for calico

Change-Id: I68b3a9f74d4b1d6d151ef699c532dde1a4d8eff4
diff --git a/metadata/service/common.yml b/metadata/service/common.yml
index 7cb5766..5e72de2 100644
--- a/metadata/service/common.yml
+++ b/metadata/service/common.yml
@@ -6,3 +6,4 @@
     common:
       network:
         engine: none
+        mtu: 1500