Revert "SEBA-357 update to latest olt-service chart"

This reverts commit eeca3fa84371cfabf952f18dab32dcc6e39f415f.

Change-Id: I9a61329e00695a9ca76fc9c21c7e0081e415ca19
diff --git a/xos-profiles/att-workflow/requirements.yaml b/xos-profiles/att-workflow/requirements.yaml
index ab99063..0f5b262 100644
--- a/xos-profiles/att-workflow/requirements.yaml
+++ b/xos-profiles/att-workflow/requirements.yaml
@@ -24,7 +24,7 @@
   version: 2.1.5
   repository: file://../../xos-services/fabric
 - name: volt
-  version: 2.1.6
+  version: 2.1.5
   repository: file://../../xos-services/volt
 - name: fabric-crossconnect
   version: 1.1.2