Fix non-literal format in printf-style calls

These were found using gcc 4.3.2-1ubuntu11 with the warning:

    warning: format not a string literal and no format arguments

Incorporated suggestions from Brandon Casey <casey@nrlssc.navy.mil>.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

fsck.c

@@ -327,7 +327,7 @@ int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
 			die("this should not happen, your snprintf is broken");
 	}
 
-	error(sb.buf);
+	error("%s", sb.buf);
 	strbuf_release(&sb);
 	return 1;
 }