audio/festvox-cmu_us_*_arctic: Fixes as suggested by jbeich

Fixes as suggested in

https://lists.freebsd.org/pipermail/svn-ports-all/2015-December/111077.html

PR: 204970
Submitted by: Michael Danilov <mike.d.ft402@gmail.com> (maintainer)
Suggested by: jbeich