Don't crash in window manager if we fail getting .apk resources.

This normally shouldn't noramlly happen, but it can in the case of
bug 6647334 (crash in LoadedApk.makeApplication) where the package
manager information becomes inconsistent, and it could also happen
if an app was uninstalled or started updating at just the right
time during a launch.

Bug: 6647334
Change-Id: Iba22efe1d646cdac46099b2135466309577dfa54