Add volume_device_name to runtest.yaml

Close-bug: PROD-19817

Change-Id: Ic06c633d296bf6e8acac10a76d3a91ca36535ec9
diff --git a/tcp_tests/templates/runtest.yml b/tcp_tests/templates/runtest.yml
index 297d3e7..c1f1599 100644
--- a/tcp_tests/templates/runtest.yml
+++ b/tcp_tests/templates/runtest.yml
@@ -30,6 +30,7 @@
         min_microversion: 2.1
         max_microversion: 2.53
         min_compute_nodes: 2
+        volume_device_name: 'vdc'
       dns_feature_enabled:
         # Switch this to designate_admin_api_enabled once [1] is promoted to stable packages
         # [1] https://gerrit.mcp.mirantis.net/gitweb?p=salt-formulas/designate.git;a=commit;h=96a3f43f6cf1149559e54a00b5548bdf46333749