Add zygote selinux permission

Addresses the following denial:
avc:  denied  { read write } for  pid=415 comm="app_process" name="3"
dev="devpts" ino=6 scontext=u:r:zygote:s0
tcontext=u:object_r:devpts:s0 tclass=chr_file

Change-Id: I7755d08d4bd226bb72fb9409f7c3deb6787b1e3e