Add exception handling for missing archives.

Change-Id: Ic2443109057207e8c31f3747b92f3457cd68998c
Reviewed-on: https://chromium-review.googlesource.com/956701Reviewed-by: Michael Moss <mmoss@chromium.org>
Commit-Queue: Prasad Vuppalapu <prasadv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542158}

tools/bisect_repackage/bisect_repackage.py

@@ -247,8 +247,13 @@ def upload_build(zip_file, context):
 def download_revision_map(context):
   """Downloads the revision map in original_gs_url in context."""
   download_file = '%s/%s' % (context.repackage_remote_path, REVISION_MAP_FILE)
-  cloud_storage.Get(context.repackage_gs_bucket, download_file,
-                    context.revision_file)
+  try:
+    cloud_storage.Get(context.original_gs_bucket,
+                      remote_file_path, zip_file_name)
+  except Exception, e:
+    logging.warning('Failed to download: %s, error: %s', zip_file_name, e)
+    return False
+  return True
 
 
 def get_revision_map(context):
@@ -350,7 +355,8 @@ def repackage_single_revision(revision_map, verify_run, staging_dir,
   archive_name = '%s_%s' %(context.file_prefix, cp_num)
   file_archive = os.path.join(staging_dir, archive_name)
   zip_file_name = '%s.zip' % (file_archive)
-  download_build(cp_num, revision_map, zip_file_name, context)
+  if not download_build(cp_num, revision_map, zip_file_name, context):
+    return
 
   extract_dir = os.path.join(staging_dir, archive_name)
   is_android = context.archive in ['arm', 'arm64']