Merging r292271:

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r292271 | aaron | 2017-01-17 21:48:31 +0000 (Tue, 17 Jan 2017) | 2 lines

Silence some Sphinx diagnostics in an attempt to get the documentation builder back to green (http://lab.llvm.org:8011/builders/llvm-sphinx-docs/builds/1895).
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llvm-svn: 295344