Fix t/directive/perlloadmodule2.t

The third test (for $url/subdir) was failing because the absence of an argument ($url?...) caused a warning that $r->arg was undefined in perlloadmodule2.pm, and the "use warnings FATAL => 'all';" line saw to it that the server returned 500/Internal Server Error in this case.

git-svn-id: https://svn.apache.org/repos/asf/perl/modperl/branches/httpd24threading@1565579 13f79535-47bb-0310-9956-ffa450edef68