package/libpcap: fix bluez circular dependency

package/libpcap: fix bluez circular dependency

The optional bluez_utils dependency of libpcap creates a circular
dependency:

$ make dbus-show-recursive-depends

Recursion detected for  : systemd
which is a dependency of: dbus
which is a dependency of: bluez_utils
which is a dependency of: libpcap
which is a dependency of: iptables
which is a dependency of: systemd
make: *** [package/dbus/dbus.mk:121: dbus-show-recursive-depends] Error 1

Drop support for bluez_utils. For bluez5_utils, which also depends on
dbus, we only need the headers in the bluez5_utils-headers package. Use
that to break the circular dependency.

Fixes:
http://autobuild.buildroot.net/results/9c3/9c3ee798fa6bb501a20a7892c0b085d2b279b664/

Suggested-by: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>