Set packages.list context to packages_list_file.

Bug: 123186697

Test: adb shell su root ls -lZd /data/system/packages.list
-rw-r----- 1 system package_info u:object_r:packages_list_file:s0 35816 2019-04-02 14:17 /data/system/packages.list

Change-Id: I62ae03b5c2acf6c703f2e4c6f49cc68825e3a785
3 files changed