help.c::uniq: plug a leak

We observe that the j-1 element can serve the same purpose as the i-1
element that we use in the strcmp(); it is either:

  1. Exactly i-1, when the loop begins (and until we see a duplicate).

  2. The same pointer that was stored at i-1 (if it was not a duplicate,
     and we just copied it into place).

  3. A pointer to an equivalent string (i.e., we rejected i-1 _because_
     it was identical to j-1).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

help.c

@@ -44,9 +44,12 @@ static void uniq(struct cmdnames *cmds)
 	if (!cmds->cnt)
 		return;
 
-	for (i = j = 1; i < cmds->cnt; i++)
-		if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
+	for (i = j = 1; i < cmds->cnt; i++) {
+		if (!strcmp(cmds->names[i]->name, cmds->names[j-1]->name))
+			free(cmds->names[i]);
+		else
 			cmds->names[j++] = cmds->names[i];
+	}
 
 	cmds->cnt = j;
 }