This bug was hidden by the "future-proofing" of the test. Sigh.
When neither GIT_CONFIG nor GIT_CONFIG_LOCAL is set, do not use NULL,
but $GIT_DIR/config. Instead of using $GIT_DIR/config when only
GIT_CONFIG_LOCAL is set. Sorry.
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>