release/21.0.52 protected

Tamara Vazquez Schroeder

@tvazquez

78634349 · Merge branch 'cherry-pick-cf1fb970 [formerly b0877c6ff8]-21.0-mc16d' into '21.0-mc16d' · Nov 28, 2017

This is the 3rd built release for 21.0-mc16d. It includes the FT0-violating MR !6727.