Simplify code.

Cases where 'loc' doesn't have any ':' or is  starting with ':' are already handled by 'ap_ir_url()'
Calling 'apr_isascii()' seems useless.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1610383 13f79535-47bb-0310-9956-ffa450edef68