Bug 959280 - Bump gaiatest to 0.21.3, r=bsilverberg
Merge pull request #15266 from jonallengriffin/gaiatest

Bug 959280 - Bump gaiatest to 0.21.3, r=bsilverberg
Revert gaia integration breake since bug 917717. a=bustage

exec-sync NodeJS module fail to build.