i386/134986: make installworld fails (FreeBSD-7.2, tr not found)

[Fernan Aguero]

As reported in the PR, the problem happens with a checkout of RELENG_7_2.
http://www.freebsd.org/cgi/query-pr.cgi?pr=i386/134986

I have just tested a checkout of RELENG_7 (STABLE) and in this case
make installworld succeeds.

-- 
fernan