js_in_body check should not fail if there is no body tag in the file
See bug 21091 comment 10 https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=21091#c10
See bug 21091 comment 10 https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=21091#c10