automount.service: Remove shared subtree mount setup

It is no longer needed to use mount `mount --make-shared` on the autofs
mountpoints, as systemd sets the root mount to MS_SHARED since version
189 [1].

[1]: https://github.com/systemd/systemd/commit/b3ac5f8cb98

misc_systemd_units/automount.service

@@ -7,7 +7,6 @@ After=basic.target
 Type=forking
 ExecStartPre=/usr/sbin/make-automaps
 ExecStart=/usr/sbin/automount -v
-ExecStartPost=/usr/bin/bash -c "for d in home jbod confidential project package scratch src pkg;do mount --make-shared /$d;done"
 PIDFile=/run/autofs-running
 ExecReload=/bin/kill -HUP $MAINPID
 Restart=always