add PRESUBMIT for native_client_sdk.

native_client_sdk/src/build_tools/update_nacl_manifest.py

Index: native_client_sdk/src/build_tools/update_nacl_manifest.py
diff --git a/native_client_sdk/src/build_tools/update_nacl_manifest.py b/native_client_sdk/src/build_tools/update_nacl_manifest.py
index 1212784a70bcb648e7c870b0625f529c9d53bfd5..7363834251e6a98a77aff33c1feac75bee976afc 100755
--- a/native_client_sdk/src/build_tools/update_nacl_manifest.py
+++ b/native_client_sdk/src/build_tools/update_nacl_manifest.py
@@ -32,7 +32,7 @@ GS_SDK_MANIFEST = GS_BUCKET_PATH + MANIFEST_BASENAME
 GS_MANIFEST_BACKUP_DIR = GS_BUCKET_PATH + 'manifest_backups/'
 
 CANARY_BUNDLE_NAME = 'pepper_canary'
-CANARY='canary'
+CANARY = 'canary'
 
 
 def SplitVersion(version_string):
@@ -378,7 +378,7 @@ class VersionFinder(object):
     """
     for platform, channel, version, _ in self.history:
       version = SplitVersion(version)
-      if with_platform == platform and channel==CANARY:
+      if with_platform == platform and channel == CANARY:
         yield channel, version
 
 
@@ -407,7 +407,7 @@ class VersionFinder(object):
       try:
         for i, platform_gen in enumerate(platform_generators):
           if platform_versions[i][1] != shared_version:
-              platform_versions[i] = platform_gen.next()
+            platform_versions[i] = platform_gen.next()
       except StopIteration:
         return
 
@@ -437,8 +437,8 @@ class VersionFinder(object):
 
     assert all(file.startswith('gs://') for file in files)
 
-    archives = [file for file in files if not file.endswith('.json')]
-    manifests = [file for file in files if file.endswith('.json')]
+    archives = [f for f in files if not f.endswith('.json')]
+    manifests = [f for f in files if f.endswith('.json')]
 
     # don't include any archives that don't have an associated manifest.
     return filter(lambda a: a + '.json' in manifests, archives)
@@ -615,7 +615,7 @@ def main(args):
   try:
     delegate = RealDelegate(dryrun=options.dryrun, gsutil=options.gsutil)
     Run(delegate, ('mac', 'win', 'linux'))
-  except Exception, e:
+  except Exception:
     if options.mailfrom and options.mailto:
       traceback.print_exc()
       scriptname = os.path.basename(sys.argv[0])