test: fix failure in test_06_purge_expunged_vm_background_task

Failures seen in
apache#10006 (comment)
and others.

With apache#9773, the response of
listManagementServers API has been changed. serviceip has been renamed
to ipaddress. THis was causing not all MS getting restarted and purge
b/g task not being able to run. The code handling API response in the
test has been updated.

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

test/integration/smoke/test_purge_expunged_vms.py

@@ -259,8 +259,8 @@ def getManagementServerIps(self):
         active_server_ips = []
         active_server_ips.append(self.mgtSvrDetails["mgtSvrIp"])
         for idx, server in enumerate(servers):
-            if server.state == 'Up' and server.serviceip != self.mgtSvrDetails["mgtSvrIp"]:
-                active_server_ips.append(server.serviceip)
+            if server.state == 'Up' and server.ipaddress != self.mgtSvrDetails["mgtSvrIp"]:
+                active_server_ips.append(server.ipaddress)
         return active_server_ips
 
     def restartAllManagementServers(self):