exclude init from apk_data_file getattr

Addresses the following auditallow spam:

avc: granted { getattr } for comm="init"
path="/data/app/com.sling-1/lib/x86/libavcodec-56.so" dev="mmcblk0p11"
ino=32607 scontext=u:r:init:s0 tcontext=u:object_r:apk_data_file:s0
tclass=file

Test: policy compiles.
Change-Id: I81775f8de93f0b4334279e9f5e19d27e6171616f