Silence some services that like to write to the console

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>

services/dhcpcd

@@ -3,4 +3,5 @@ type once
 target boot
 after dhcpcdmaster network
 
+tty /dev/null
 exec dhcpcd -n %0

services/dhcpcdmaster

@@ -2,6 +2,7 @@ description "DHCP client - master service"
 type wait
 target boot
 after network
+tty /dev/null
 
 exec {
 	mkdir -p /var/db/dhcpcd

services/sysctl

@@ -1,4 +1,5 @@
 description configure kernel paramters
+tty /dev/null
 exec sysctl --system
 type wait
 target boot