Revert "Refactor mechanism driver metadata"

This reverts commit 79ffa26858d682f404984175dc1ab93863a149ad.

Fixes PROD-14994

Change-Id: I8dc05999dd072b3249831a7ef01d07831e46db0f
diff --git a/tests/pillar/gateway_qos.sls b/tests/pillar/gateway_qos.sls
index f5c3b0b..fea882e 100644
--- a/tests/pillar/gateway_qos.sls
+++ b/tests/pillar/gateway_qos.sls
@@ -5,8 +5,8 @@
       engine: ml2
       tenant_network_types: "flat,vxlan"
       mechanism:
-        - openvswitch
-        - l2population
+        ovs:
+          driver: openvswitch
     dvr: false
     enabled: true
     qos: true