mcstrans: start early and stop late

It stopped too early, exposing a bug in sudo selinux_restore_tty():

SELINUX_ERR op=setxattr invalid_context="wheel.id:wheel.role:users.terminals.pty.pty_file:SystemLow"
avc:  denied  { mac_admin } for  pid=859 comm="sudo" capability=33 scontext=wheel.id:wheel.role:sudo.wheel.subj:s0 tcontext=wheel.id:wheel.role:sudo.wheel.subj:s0 tclass=capability2 permissive=0

If we want to be able to reference human readable contexts in SELinuxContext= and nspawn -Z and -L then we need mcstrans ASAP

v2: stop late, but do stop
Signed-off-by: Dominick Grift <dac.override@gmail.com>
Acked-by: Petr Lautrbach <plautrba@redhat.com>

mcstrans/src/mcstrans.service

@@ -2,6 +2,9 @@
 Description=Translates SELinux MCS/MLS labels to human readable form
 Documentation=man:mcstransd(8)
 ConditionSecurity=selinux
+DefaultDependencies=no
+Before=shutdown.target sysinit.target
+Conflicts=shutdown.target
 
 [Service]
 ExecStart=/sbin/mcstransd -f