When updating an existing configuration file, we did not always
close the filehandle that is reading from the current configuration
file when we encountered an error (e.g. when unsetting a variable
that does not exist).
Signed-off-by: Sven Strickroth <email@cs-ware.de> Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com> Reviewed-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>