Adding permissions needed to remove cache

During removing cache data using Zipper application, I found violation logs.

avc:  denied  { write } for  pid=198 comm="installd" name="cache" dev="mmcblk0p29" ino=81680 scontext=u:r:installd:s0 tcontext=u:object_r:download_file:s0 tclass=dir
avc:  denied  { remove_name } for  pid=198 comm="installd" name="downloadfile.apk" dev="mmcblk0p29" ino=82247 scontext=u:r:installd:s0 tcontext=u:object_r:download_file:s0 tclass=dir
avc:  denied  { unlink } for  pid=198 comm="installd" name="downloadfile.apk" dev="mmcblk0p29" ino=82247 scontext=u:r:installd:s0 tcontext=u:object_r:download_file:s0 tclass=file

Reproduction path is like below
1. Downloading Zipper application from Google Play (I used Zipper 1.9.9.2)
2. Clicking option and clicking "removing cache" button
3. Select "yes"
4. Violation show up

Change-Id: I7993f1d20e3aa4c3e19c4aba9b4bef6760831a87