restore logic for icmp and null ports
diff --git a/openstack/compute/v2/extensions/secgroups/requests.go b/openstack/compute/v2/extensions/secgroups/requests.go
index 1cdbde0..ec8019f 100644
--- a/openstack/compute/v2/extensions/secgroups/requests.go
+++ b/openstack/compute/v2/extensions/secgroups/requests.go
@@ -104,9 +104,9 @@
 	// the ID of the group that this rule will be added to.
 	ParentGroupID string `json:"parent_group_id" required:"true"`
 	// the lower bound of the port range that will be opened.
-	FromPort int `json:"from_port" required:"true"`
+	FromPort int `json:"from_port"`
 	// the upper bound of the port range that will be opened.
-	ToPort int `json:"to_port" required:"true"`
+	ToPort int `json:"to_port"`
 	// the protocol type that will be allowed, e.g. TCP.
 	IPProtocol string `json:"ip_protocol" required:"true"`
 	// ONLY required if FromGroupID is blank. This represents the IP range that