SecurityGroupRuleExists should point out rule id inseand of group id

When we get a SecurityGroupRuleExists, we want to get the rule id
instaed of group id, and this is what the fucntion
_check_for_duplicate_rules() does.

Change-Id: I9b526d9829582cb26bfda98bcaf1704fe8681cbe
Closes-bug:  #1354343
Merge "SecurityGroupRuleExists should point out rule id inseand of group id"
Merge remote-tracking branch 'origin/master' into csr1kv_for_routing_juno_minimal