Trivial: Delete a definition that is not needed.

servers = [] is redundant, delete it for the code clean.

Change-Id: Id3b0bfd7af4e6aa8612860b347c388784d7dd8fc
diff --git a/tempest/common/compute.py b/tempest/common/compute.py
index 8e9f0b0..318eb10 100644
--- a/tempest/common/compute.py
+++ b/tempest/common/compute.py
@@ -129,7 +129,6 @@
                                                 **kwargs)
 
     # handle the case of multiple servers
-    servers = []
     if multiple_create_request:
         # Get servers created which name match with name param.
         body_servers = clients.servers_client.list_servers()