LAKITU: Get the toolchain from gs://cos-sdk

BUG=b/177367546
TEST=presubmit
RELEASE_NOTE=None

Change-Id: Ic29682fb72912988f61f5b4cf6f8a783777a0278
(cherry picked from commit 5046b4368b8a3bf275fdf852ad7ca6c85c2e5025)

lib/constants.py

diff --git a/lib/constants.py b/lib/constants.py
index 4f3a8b0..d57f15b 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -655,7 +655,7 @@
                             'chromeos/config/chromeos_version.sh')
 SDK_VERSION_FILE = os.path.join(PUBLIC_BINHOST_CONF_DIR,
                                 'host/sdk_version.conf')
-SDK_GS_BUCKET = 'chromiumos-sdk'
+SDK_GS_BUCKET = 'cos-sdk'
 
 PUBLIC = 'public'
 PRIVATE = 'private'

scripts/cros_sdk.py

diff --git a/scripts/cros_sdk.py b/scripts/cros_sdk.py
index 286354d..ec864ea 100644
--- a/scripts/cros_sdk.py
+++ b/scripts/cros_sdk.py
@@ -86,7 +86,7 @@
   extension = {'bz2': 'tbz2', 'xz': 'tar.xz'}
   return [
       toolchain.GetSdkURL(
-          suburl='cros-sdk-%s.%s' % (version, extension[compressor]))
+          suburl='%s.%s' % (version, extension[compressor]))
       for compressor in COMPRESSION_PREFERENCE
   ]