Merge pull request #12656 from alalek:fix_documentation_build
authorAlexander Alekhin <alexander.a.alekhin@gmail.com>
Fri, 28 Sep 2018 14:16:25 +0000 (14:16 +0000)
committerAlexander Alekhin <alexander.a.alekhin@gmail.com>
Fri, 28 Sep 2018 14:16:25 +0000 (14:16 +0000)

Trivial merge