Set pm.BackgroundDexOptService as the source of true

The real dexopt maintainance job is
com.android.server.pm.BackgroundDexOptService, and not
com.android.server.BackgroundDexOptJobService

Partial revert of commit 096d304a.

Test: manual inspection
Bug: 36140426

(partial cherry picked from commit
91d40f1b)

Merged-In: I983ac91117f107282095fa7eefdbce08e0dcfce3
Change-Id: I983ac91117f107282095fa7eefdbce08e0dcfce3

# Conflicts:
#	core/res/AndroidManifest.xml
#
services/core/java/com/android/server/pm/PackageManagerService.java
#	services/java/com/android/server/SystemServer.java