Reënable stats downloading

I'm running out of ideas to keep these commit messages entertaining. Thankfully this should keep the CI green and we can forget any of it ever happened.

Author: gaearon

scripts/circleci/build.sh

@@ -5,7 +5,7 @@ set -e
 # Update the local size measurements to the master version
 # so that the size diff printed at the end of the build is
 # accurate.
-#curl -o scripts/rollup/results.json http://react.zpao.com/builds/master/latest/results.json
+curl -o scripts/rollup/results.json http://react.zpao.com/builds/master/latest/results.json
 
 yarn build --extract-errors
 # Note: since we run the full build including extracting error codes,