units: make sure proc-sys-binfmt_misc.automount is actually stopped

As with other units, stopping of the automount requires actual work,
and without the ordering dependency systemd might not execute the stop
job before shutdown.target is reached and units ordered after that are
executed.

units/proc-sys-fs-binfmt_misc.automount

@@ -18,6 +18,7 @@ ConditionPathIsReadWrite=/proc/sys/
 DefaultDependencies=no
 Before=sysinit.target
 Conflicts=shutdown.target
+Before=shutdown.target
 
 [Automount]
 Where=/proc/sys/fs/binfmt_misc