Fix of intermittent hang when building Aar files. This is an untested…

… fix because the hang cannot be reproduced on demand, but not calling System.exit() has caused the same problem previously in both AndroidResourceProcessingAction and AarGeneratorAction. Mimics the exception handling behavior in AndroidResourceProcessingAction, which is not known to cause any hangs.

--
MOS_MIGRATED_REVID=96911485

src/tools/android/java/com/google/devtools/build/android/AarGeneratorAction.java

@@ -16,7 +16,6 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
 import com.google.common.base.Stopwatch;
-import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableList;
 import com.google.common.hash.Hashing;
 import com.google.devtools.build.android.Converters.DependencyAndroidDataListConverter;
@@ -43,6 +42,7 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
@@ -162,7 +162,8 @@ public static void main(String[] args) {
           String.format("Packaging finished at %dms", timer.elapsed(TimeUnit.MILLISECONDS)));
 
     } catch (IOException | MergingException e) {
-      throw Throwables.propagate(e);
+      logger.log(Level.SEVERE, "Error during merging resources", e);
+      System.exit(1);
     }
     System.exit(0);
   }