Remove [max|min max] from the LuaScope syntax, since the 'server' scope is not implemented yet.

Add the 'thread' value to the list of possible scopes

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1367592 13f79535-47bb-0310-9956-ffa450edef68