[CVP] Skip flannel interfaces from  test_single_vip_exists (it is a case for k8s clusters)

Change-Id: I9b470da565a233cc1cf222b3bd620bc3de73ecd0
Related-PROD: PROD-30137
diff --git a/test_set/cvp-sanity/tests/test_single_vip.py b/test_set/cvp-sanity/tests/test_single_vip.py
index 7a1c2f8..c18c660 100644
--- a/test_set/cvp-sanity/tests/test_single_vip.py
+++ b/test_set/cvp-sanity/tests/test_single_vip.py
@@ -1,5 +1,6 @@
 import utils
 import json
+import pytest
 
 
 def test_single_vip_exists(local_salt_client):
@@ -7,15 +8,23 @@
        within one group of nodes (where applicable).
        Steps:
        1. Get IP addresses for nodes via salt cmd.run 'ip a | grep /32'
-       2. Check that at least 1 node responds with something.
+       2. Check that exactly 1 node responds with something.
     """
     groups = utils.calculate_groups()
+
+    keywords_to_exclude_interfaces = ["flannel.1"]
+    exclude_from_grep =  " | grep -v {}".format('\|'.join(keywords_to_exclude_interfaces)) \
+                        if len(keywords_to_exclude_interfaces) > 0 \
+                        else ""
     no_vip = {}
     for group in groups:
         if group in ['cmp', 'cfg', 'kvm', 'cmn', 'osd', 'gtw']:
             continue
         nodes_list = local_salt_client.cmd(
-            "L@" + ','.join(groups[group]), 'cmd.run', 'ip a | grep /32', expr_form='compound')
+            tgt="L@" + ','.join(groups[group]),
+            fun='cmd.run',
+            param='ip a | grep /32 ' + exclude_from_grep,
+            expr_form='compound')
         result = [x for x in nodes_list.values() if x]
         if len(result) != 1:
             if len(result) == 0: