Improve security groups management.

- Add create_security_group_rule method to base class
  to make easier creating rules for IPv6 test cases.
- Add delete_security_group method.
- Make sure segurity groups are deleted using the
  client that has been used to create them.
- Improve security group client handling.

Change-Id: I50858d5198d8a70a2bb9fb278786c433d7cb12ca
diff --git a/neutron_tempest_plugin/common/constants.py b/neutron_tempest_plugin/common/constants.py
index 4dc7844..f695f6c 100644
--- a/neutron_tempest_plugin/common/constants.py
+++ b/neutron_tempest_plugin/common/constants.py
@@ -171,3 +171,11 @@
 # Possible types of values (e.g. in QoS rule types)
 VALUES_TYPE_CHOICES = "choices"
 VALUES_TYPE_RANGE = "range"
+
+# Security group parameters values mapped by IP version
+DEFAULT_SECURITY_GROUP_RULE_PARAMS = {
+    lib_constants.IP_VERSION_4: {'ethertype': lib_constants.IPv4,
+                                 'remote_ip_prefix': lib_constants.IPv4_ANY},
+    lib_constants.IP_VERSION_6: {'ethertype': lib_constants.IPv6,
+                                 'remote_ip_prefix': lib_constants.IPv6_ANY},
+}