Remove `fails_with :llvm`
Remove `fails_with :llvm`

Upstream Homebrew doesn't support this compiler so there is no need for
us to either.

See Homebrew/homebrew-core@275d507

castiron/puppet-mysql,castiron/puppet-mysql,boxen/puppet-mysql,boxen/puppet-mysql,boxen/puppet-mysql,castiron/puppet-mysql