Fix wake lock leak

Wake lock was not being released when installation failed
due to early bail out call.  I wrapped the calls into
a try/finally to ensure it gets released.

Code was tested by tweaking the code to force a failure
and test installing/uninstalling apps.

BUG: 25814793
Change-Id: I2e81e5d76edcfb601ce734cf571705e979c51f32