Ok, I don't have a FreeBSD box to test this.

Maybe the better solution is what's in the Ubuntu 13.10 support for Apache 2.4, but in https://github.com/puppetlabs/puppetlabs-apache/pull/552/files#diff-2f383a197b1a428561b364755701d60eR39 have case statements and specifying the right default version per OS, and then you don't need this fact at all.