BUILD: dev/phash: remove the accidentally committed a.out file

BUILD: dev/phash: remove the accidentally committed a.out file

Commit 41f28b3c53 ("DEV: phash: Update 414 and 431 status codes to phash")
accidentally committed a.out, resulting in build/checkout issues when
locally rebuilt. Let's drop it.

This should be backported to 3.1.

(cherry picked from commit e34a0a50ae1a1da031fb9ef82c1941f6ece0d24f)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 4ca1814f87d4804361aaf35b2f567c6ba3ce207e)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>