In library policy dashboard, sometimes the same rule is
repeated multiple times, overwriting some subsequent rules.
For example, in Policy Details: TagBasedNetworkSecurityZone,
the first two rules displays as
security_zone_tags('demo_zone'),
security_zone_tags('demo_zone')
rather than the correct
security_zone_tags('demo_zone'),
security_zone_tags('production_zone').
This patch fixes the issue by making sure a distinct ID is
assigned to each rule for django.
Change-Id: I20d758ec4dffeaecf60f6c60c401bb08e359def5
Closes-Bug: 1784770
7570aa4d41