httpd: if range is not specified, correctly fall back to read/write loop

range_start was staying -1, and comparison meant to detect
"is it the first sendfile that failed, or not the first?"
was making incorrect decision. The result: nothing is sent.

function                                             old     new   delta
send_file_and_exit                                   865     877     +12

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed