Populate mPackages with system pkg even if installed is better

System initialization relied on the system package living in mPackages
in order to build the expectingBetter map and successfully recover in
the case that we fail to scan / parse the updated APK. With this change
we properly populate mPackages in this scenario.

Test: manual - artificially force scan failure and reboot
Change-Id: Id86b579722bdfde8d4e660da3b680b0305a1d7e2
Fixes: 79428784
Fixes: 79360948