httpd: fix offset for sendfile

If the Range: header is not present it the request,
the offset passed to sendfile is wrong,
and httpd falls back to the read-write loop.

function                                             old     new   delta
send_file_and_exit                                   857     865      +8
handle_incoming_and_exit                            2239    2230      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 8/-9)               Total: -1 bytes

Signed-off-by: Maxim Storchak <m.storchak@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed