Add nosec in get_free_segmentation_id function

pep8 job fails due to bandit check with an error:
    [B311:blacklist] Standard pseudo-random generators are not suitable 
    for security/cryptographic purposes.

But using the standard random function in the get_free_segmentation_id 
function is suitable, so adding #nosec comment should unbblock the gate.

Change-Id: Iad8e376c503a32300b3e0b504f47a0c81e53a7a8

patrole_tempest_plugin/tests/api/network/test_segments_rbac.py

@@ -46,7 +46,7 @@ def get_free_segmentation_id(cls):
         # With 2+ concurrency, tests that ran in the same moment may fail due
         # to usage conflict. To prevent it we select segmentation to start
         # randomly.
-        segmentation_id = random.randint(1000, 5000)
+        segmentation_id = random.randint(1000, 5000)  # nosec
         while segmentation_id in segmentation_ids:
             segmentation_id += 1