add SIOCGIFINDEX to list of unprivileged socket ioctls

Addresses
avc: denied { ioctl } for path="socket:[69748]" dev="sockfs" ino=69748
ioctlcmd=8933 scontext=u:r:untrusted_app:s0:c512,c768
tcontext=u:r:untrusted_app:s0:c512,c768 tclass=udp_socket

Change-Id: Iee3821ade9dc044fa03705902923ed18c91425dd