Documentation/Makefile: remove cmd-list.made before redirecting to it.

If cmd-list.made has been created by a previous run as root, output
redirection to it will fail.  So remove it before regeneration.

Signed-off-by: David Kastrup <dak@gnu.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -119,6 +119,7 @@ cmds_txt = cmds-ancillaryinterrogators.txt \
 $(cmds_txt): cmd-list.made
 
 cmd-list.made: cmd-list.perl $(MAN1_TXT)
+	$(RM) $@
 	perl ./cmd-list.perl
 	date >$@