Small fix: test nodes in ElasticSearch will get > than 500 nodes

Some big Production clouds have more than 500 nodes in total.
So the test is not valid for such cloud: it will fetch only
500 nodes instead of all nodes of the cloud. Changing the request
to fetch 1000 nodes.

Change-Id: I58493fc55e1deb2c988d61e7c8a4f8ed971a60d4
diff --git a/test_set/cvp-sanity/tests/test_stacklight.py b/test_set/cvp-sanity/tests/test_stacklight.py
index 491c1ee..bd6401d 100644
--- a/test_set/cvp-sanity/tests/test_stacklight.py
+++ b/test_set/cvp-sanity/tests/test_stacklight.py
@@ -69,7 +69,7 @@
     proxies = {"http": None, "https": None}
     data = ('{"size": 0, "aggs": '
             '{"uniq_hostname": '
-            '{"terms": {"size": 500, '
+            '{"terms": {"size": 1000, '
             '"field": "Hostname.keyword"}}}}')
     response = requests.post(
         'http://{0}:9200/log-{1}/_search?pretty'.format(IP, today),