Convert existing die(..., strerror(errno)) to die_errno()

Change calls to die(..., strerror(errno)) to use the new die_errno().

In the process, also make slight style adjustments: at least state
_something_ about the function that failed (instead of just printing
the pathname), and put paths in single quotes.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-fetch--tool.c

@@ -8,7 +8,7 @@ static char *get_stdin(void)
 {
 	struct strbuf buf = STRBUF_INIT;
 	if (strbuf_read(&buf, 0, 1024) < 0) {
-		die("error reading standard input: %s", strerror(errno));
+		die_errno("error reading standard input");
 	}
 	return strbuf_detach(&buf, NULL);
 }