Skip checking `ENV` env var
Skip checking `ENV` env var

And rely on `SENTRY_DSN` exclusively when enabling
Sentry.

craigcitro/travis-build,kevmoo/travis-build,JuliaCI/travis-build,kevmoo/travis-build,andyli/travis-build,andyli/travis-build,craigcitro/travis-build,JuliaCI/travis-build