ART: Fix unclosed files in dex2oat

Under some error conditions files are not closed, and the close guard
will complain.

Bug: 18603475

(cherry picked from commit d97465c3742cc3c82843665f2678b881de29854b)

Change-Id: I7155e3f4f6231844edd375b9302ecf1ba8079950
1 file changed