Existing violations allow bypassing policy rules when adding new replicas

Steps to reproduce:

• start with an empty cluster policy.
• create a collection with as many replicas as there are nodes.
• add one more replica to any node. Now this node has two replicas, all other nodes have one. 
• define the following cluster policy:

{ 'set-cluster-policy': [ {'replica': '<2', 'shard': '#ANY', 'node': '#ANY', 'strict': true} ] } 

This automatically creates a violation because of the existing layout.

• try adding one more replica. This should fail because no node satisfies the rules (there must be at most 1 replica per node). However, the command succeeds and adds replica to the node that already has 2 replicas, which clearly violates the policy and makes matters even worse.