file: patch process stdin to /dev/null

file: patch process stdin to /dev/null

This prevents broken pipe errors in executed child processes that
attempt to access stdin.

Suggested-by: Vytautas Virvičius <vy.virvicius@gmail.com>
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
(cherry picked from commit 67118a6b334cd50c9f39a0c04506befd49bf592a)