Fix duplicate check for ACL rules with cidr

While checking for duplicate ACL rules, we were ignoring the prefix part. As a result, if two rules containing different prefixes were being added, we were treating them duplicates and were not adding the second rule. Added comparison of prefixes while comparing rules.

Also updated the unit test case for the same.

Change-Id: I1dc1669826e3f9154f2876074c0eada58b59ac29
Closes-Bug: 1392545
(cherry picked from commit ee517d7468350b3da719f92009c661a1ee6dd1f7)