Remove wrong external_crx paths in json file for default apps

BUG=chromium:295821
TEST=manual, gmerge chromeos-default-apps, remove cache /var/cache/external_cach/*.crx and login as new user

Change-Id: I771ea565904966990c4158e9219307bfc34eb457
Reviewed-on: https://chromium-review.googlesource.com/170200
Tested-by: Dmitry Polukhin <dpolukhin@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Dmitry Polukhin <dpolukhin@chromium.org>
diff --git a/scripts/chrome_update_extension_cache.py b/scripts/chrome_update_extension_cache.py
index 913833e..2150ce1 100644
--- a/scripts/chrome_update_extension_cache.py
+++ b/scripts/chrome_update_extension_cache.py
@@ -32,7 +32,6 @@
 from chromite.lib import osutils
 
 
-EXTENSIONS_CACHE_PREFIX = '/usr/share/google-chrome/extensions'
 UPLOAD_URL_BASE = 'gs://chromeos-localmirror-private/distfiles'
 
 
@@ -66,12 +65,8 @@
   osutils.WriteFile(os.path.join(crxdir, 'extensions', filename),
                     response.read())
 
-  # Has to delete because only one of 'external_crx' or
-  # 'external_update_url' should present for the extension.
-  del extension['external_update_url']
-
-  extension['external_crx'] = os.path.join(EXTENSIONS_CACHE_PREFIX, filename)
-  extension['external_version'] = version
+  # Keep external_update_url in json file, ExternalCache will take care about
+  # replacing it with proper external_crx path and version.
 
   cros_build_lib.Info('Downloaded, current version %s', version)
   return True