git cl upload: remove no longer aplicable message.

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index 1a151c7b00352087da54aa61e8d1c4725423c39f..56c0ff77189b8fd873532ad9c37ef7620060473f 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -2483,11 +2483,10 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
         # Gerrit will create additional CLs when uploading.
         if not parent or (RunGitSilent(['rev-parse', upstream_branch + ':']) !=
                           RunGitSilent(['rev-parse', parent + ':'])):
-          # TODO(tandrii): remove "old depot_tools" part on April 12, 2016.
           DieWithError(
               'Upload upstream branch %s first.\n'
-              'Note: maybe you\'ve uploaded it with --no-squash or with an old '
-              'version of depot_tools. If so, then re-upload it with:\n'
+              'Note: maybe you\'ve uploaded it with --no-squash. '
+              'If so, then re-upload it with:\n'
               '    git cl upload --squash\n' % upstream_branch_name)
       else:
         parent = self.GetCommonAncestorWithUpstream()