Fix tagging Instances and Network Ports

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1539584

Fix tagging Instances/Network Ports from the list of Instances/Network Ports,
accessed through Networks -> Security Groups, opening some security group and
clicking on Instances/Network Ports under Relationships table.

app/controllers/security_group_controller.rb

@@ -23,9 +23,13 @@ def button
     @refresh_div = "main_div"
 
     case params[:pressed]
+    when "instance_tag"
+      return tag("VmOrTemplate")
+    when "network_port_tag"
+      return tag("NetworkPort")
     when "security_group_tag"
       return tag("SecurityGroup")
-    when 'security_group_delete'
+    when "security_group_delete"
       delete_security_groups
     when "security_group_edit"
       javascript_redirect :action => "edit", :id => checked_item_id(params)