userspace: inittab: fix rsyslog invocation

rsyslogd forks and daemonizes by default. So we can't "respawn" from
inittab. The option to avoid forking also prints massive diagnostic
information, so let's fire it once only.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

userspace/rootfs_override/etc/inittab

@@ -28,7 +28,7 @@ ttyGS0::respawn:/bin/ash --login
 ttyS0::respawn:/bin/ash --login
 
 # Logging junk
-null::respawn:/usr/sbin/rsyslogd
+null::sysinit:/usr/sbin/rsyslogd
 
 # Stuff to do before rebooting
 null::shutdown:/usr/bin/killall rsyslogd