racoon: allow ioctl TUNSETIFF

Used by
https://android.googlesource.com/platform/external/ipsec-tools/+/bf16586a33b1432a11526754523fceb62944dc1c/main.c#116

Addresses the following denial:

audit(0.0:8126): avc: denied { ioctl } for comm="racoon" path="/dev/tun" dev="tmpfs" ino=25329 ioctlcmd=0x54ca scontext=u:r:racoon:s0 tcontext=u:object_r:tun_device:s0 tclass=chr_file permissive=0

Test: policy compiles.
Change-Id: Ia26077d4a9e810c7006d4b979d6b7e9ca154b485