Add a NULL terminator after protocol buffer messages.
Add a NULL terminator after protocol buffer messages.

mgiannikouris/vi-firmware,mgiannikouris/vi-firmware,ene-ilies/vi-firmware,openxc/vi-firmware,openxc/vi-firmware,openxc/vi-firmware,ene-ilies/vi-firmware,ene-ilies/vi-firmware,mgiannikouris/vi-firmware,openxc/vi-firmware,mgiannikouris/vi-firmware,ene-ilies/vi-firmware