The msleep_interruptible function appears only in 2.6.9 and up, but we
can supply it for older kernels.

I saw a Fedora Core system with a 2.6.7 kernel for which this test
didn't work.  Our FC2 install disc comes with 2.6.5, for which this
test works, and the current FC2 kernel is 2.6.10, so I'm putting the
issue on the far back burner for now.