package/bluez5_utils: ensure build order with the headers-only variant

Since bluez5_utils and bluez5_utils-headers would install the same set
of files (headers), we want to ensure the former is run after the
latter.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Grzegorz Blach <grzegorz@blach.pl>
Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>