Fail early if we fail to parse frameworks-res.apk.

If we fail to parse this APK, there will be no mapping for "android" in
mPackages, resulting in NUllPointerException's later during boot in code
that reasonably assumes that it is present. This may result in some poor
sap wasting days trying to diagnose a trivial error in the frameworks
manifest file, trying to spot the single warning earier in the log that
caused the problem.

Instead, fail early, so that the relevant warning in the log will be just
before the exception, rather then several pages back.

Test: Make a change to core/res/AndroidManifest.xml that results in
Test: the parser failing, and verify that it throws here rather then
Test: later. Verified that it does *not* throw here when everything
Test: is ok.

Change-Id: I4d0c5e935e1e29ad70566808783045f33dbc1114