Move build fingerprint check outside of main loop

Per discussion in ag/9915756, call PM.isDeviceUpgrading once
outside of the main loop when restoring staged sessions.

Test: atest StagedInstallTest#testInstallApkChangingFingerprint
Bug: 140992644
Change-Id: I65ac48e49364706857670dee96e47584c3a19295
1 file changed