Lower mtu on virt computes

Change-Id: I9cd47674fdc7acd11e1a6e6c7ba77a0a20c964d9
Related: https://mirantis.jira.com/browse/PROD-15929
diff --git a/classes/cluster/virtual-mcp-ocata-ovs/openstack/compute.yml b/classes/cluster/virtual-mcp-ocata-ovs/openstack/compute.yml
index 7a25b90..938ab7b 100644
--- a/classes/cluster/virtual-mcp-ocata-ovs/openstack/compute.yml
+++ b/classes/cluster/virtual-mcp-ocata-ovs/openstack/compute.yml
@@ -13,7 +13,7 @@
     primary_interface: ens4
     tenant_interface: ens5
     external_interface: ens6
-    interface_mtu: 9000
+    interface_mtu: 1500
     linux_system_codename: xenial
   nova:
     compute: