package/iputils: add SELinux module

package/iputils: add SELinux module

Support for the iputils is added by the admin/netutils module in the
SELinux refpolicy for the following tools :
 - arping
 - ping
 - tracepath
 - traceroute6

Support for rdisc is added by services/rdisc.

Support for tftpd is added by services/tftp.

Note: listing the same SELinux module multiple times is OK, as the list
of modules is eventually $(sort)ed anyway.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
[yann.morin.1998@free.fr: simplifications to only use positive logic]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>