Use Akismet::build_query() instead of build_query().

Specifically, do this because we want the default behavior of PHP's http_build_query (when the arg separator is specified), and there's no value in using WP's http_build_query replacement _http_build_query with alternate arguments.


git-svn-id: https://plugins.svn.wordpress.org/akismet/trunk@967476 b8457f37-d9ea-0310-8a92-e5e31aec5664