Fixed PackageManager.readLPw() call.

It wasn't including pre-created users; as such, apps that were not
installed on pre-created users got installed on reboot.

To test it:

adb shell pm create-user --pre-create-only
m ApiDemos
adb install --user current ~/Downloads/apk/ApiDemos.apk
adb shell dumpsys package com.example.android.apis |egrep ".*User .*:"|grep installed
adb shell stop && adb shell start
adb shell dumpsys package com.example.android.apis |egrep ".*User .*:"|grep installed

Without this fix, the second dumpsys would show the app installed
for the pre-created user.

Test: manual test (see above)
Test: atest CtsMultiUserHostTestCases:android.host.multiuser.PreCreateUsersTest
Bug: 160252062

Change-Id: I46c2ec94a3ab422e3e39b66239c21fb6cbff5a8e