netd: fix denial for wifi sharing

avc:  denied  { search } for  pid=655 comm="netd" name="misc" dev="mmcblk0p28" ino=1032193 scontext=u:r:netd:s0 tcontext=u:object_r:dhcp_data_file:s0 tclass=dir

Change-Id: I7ba1002b8b81948033506ad4d1fe64c44904e60d
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>