vif.c:info_version() - Fix Clang complaint on FreeBSD

Should remove the need for the following patch in ports:

  https://svnweb.freebsd.org/ports/head/net/mrouted/files/patch-vif.c

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
ChangeLog: More on the FreeBSD fixes :)

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>