Populate fields for committed staged sessions

Those fields are needed for pre-reboot verification and
installation after reboot.

Bug: 181731810
Test: atest StagedInstallTest StagedInstallInternalTest
Test: 1. `adb install --staged SOMEAPP`
      2. reboot the device before the session reaches READY
      3. `adb shell pm list staged-sessions` after boot completed
      4. check the session is READY instead of FAILED
Change-Id: I3de3336cdfac9b925ba6ebb981db773e3a566047