Remove dns servers from server_signal template

There is no way to overwrite dns servers list, so
remove them to use cluster network settings directly.

Change-Id: I08350018d348684256d32b5f37117c21babc6ab5
Closes-Bug: PRODX-5293
(cherry picked from commit 1db1ea67c652914adfa1a127236a8662bf4de1f7)
(cherry picked from commit 366c608407a5837b18eab7db2b66e4bfbd00d51a)
diff --git a/heat_tempest_plugin/tests/scenario/templates/test_server_signal.yaml b/heat_tempest_plugin/tests/scenario/templates/test_server_signal.yaml
index 4556a2f..bb8f90c 100644
--- a/heat_tempest_plugin/tests/scenario/templates/test_server_signal.yaml
+++ b/heat_tempest_plugin/tests/scenario/templates/test_server_signal.yaml
@@ -20,9 +20,6 @@
   private_net:
     type: string
     default: heat-net
-  dns_servers:
-    type: comma_delimited_list
-    default: ["8.8.8.8", "8.8.4.4"]
   user_data_format:
     type: string
     default: RAW
@@ -55,7 +52,6 @@
       network: {get_resource: network}
       ip_version: 4
       cidr: {get_param: subnet_cidr}
-      dns_nameservers: {get_param: dns_servers}
 
   router:
     type: OS::Neutron::Router