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.

diff --git a/dev/phash/a.out b/dev/phash/a.out
deleted file mode 100755 (executable)
index 3da1dd8..0000000
Binary files a/dev/phash/a.out and /dev/null differ