Add 'kernel too old' warning to ofpath

* ofpath: On Windtunnel warn when the kernel is too old for proper
  support.  The warning message is sent to stderr so it will not
  interfere with scripts or other automated invocation of ofpath.
git-archimport-id: erbenson@alaska.net--public/yaboot--devel--1.3--patch-44
3 files changed