[l2h] calling latex2html with -dir . fails

[Daniel Gildea]

> Calling with -dir . leads to errors instead of the expected run with the
> same result as not setting -dir at all.  It is not so important, as it
> is always possible to avoid using -dir at all, but still.

Should be fixed in github.  Since "-dir ." does not create a
subdirectory for the html files, it actually is not the same as the
defualt behavior.  However, the option "-rootdir ." is the same
as the default behavior.