Fix typo in show-index.c

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/show-index.c b/show-index.c
index c21d660..a30a2de 100644
--- a/show-index.c
+++ b/show-index.c
@@ -8,7 +8,7 @@
 	static unsigned int top_index[256];
 
 	if (fread(top_index, sizeof(top_index), 1, stdin) != 1)
-		die("unable to read idex");
+		die("unable to read index");
 	nr = 0;
 	for (i = 0; i < 256; i++) {
 		unsigned n = ntohl(top_index[i]);