Bump Gsutil version for download_from_google_storage to 4.15

download_from_google_storage.py

Index: download_from_google_storage.py
diff --git a/download_from_google_storage.py b/download_from_google_storage.py
index 097861798018cf4f6322d9686253972d08dcce1f..dd6eea329d73924a2762545e3477871ab96dc074 100755
--- a/download_from_google_storage.py
+++ b/download_from_google_storage.py
@@ -55,7 +55,7 @@ def GetNormalizedPlatform():
 class Gsutil(object):
   """Call gsutil with some predefined settings.  This is a convenience object,
   and is also immutable."""
-  def __init__(self, path, boto_path=None, timeout=None, version='4.7'):
+  def __init__(self, path, boto_path=None, timeout=None, version='4.15'):
     if not os.path.exists(path):
       raise FileNotFoundError('GSUtil not found in %s' % path)
     self.path = path