[l2h] kpsewhich check doesn't match mine

[Stephen Gildea]

LaTeX2HTML config.pl runs kpsewhich as follows: kpsewhich -show-path=tex

But this doesn't work, at least not for my kpsewhich.  I want:
kpsewhich -show-path=.tex  (need that dot in ".tex")

Oddly, kpsewhich does not consider it an error that its only argument
is failing, and it exits successfully.  So my latex2html configure
script runs to the end, only slightly wrong.

I have LaTeX2HTML release 2K.1beta and kpathsea version 3.1.