Another config file parsing fix.

Another config file parsing fix.

If the variable we need to store should go into a section
that currently only has a single variable (not matching
the one we're trying to insert), we will already be into
the next section before we notice we've bypassed the correct
location to insert the variable.

To handle this case we store the current location as soon
as we find a variable matching the section of our new
variable.

This breakage was brought up by Linus.

Signed-off-by: Sean Estabrooks <seanlkml@sympatico.ca>
Signed-off-by: Junio C Hamano <junkio@cox.net>