[varnishcache/varnish-cache] aed3e6: Fix another warning spotted on FreeBSD

[Federico G. Schwindt]

  Branch: refs/heads/master
  Home:   https://github.com/varnishcache/varnish-cache
  Commit: aed3e68fd0c32904c1435cf010789d29883600e6
      https://github.com/varnishcache/varnish-cache/commit/aed3e68fd0c32904c1435cf010789d29883600e6
  Author: Federico G. Schwindt <fgsch at lodoss.net>
  Date:   2015-12-14 (Mon, 14 Dec 2015)

  Changed paths:
    M bin/varnishstat/varnishstat_curses.c

  Log Message:
  -----------
  Fix another warning spotted on FreeBSD