add error code logging to unwrap command

src/unwrap.c

@@ -101,6 +101,7 @@ static int unwrap(
 		if (status != EC3_SUCCESS) {
 			b_err("I/O failure while reading from container",
 			      in_path);
+			b_i("error code: %s", ec3_status_to_string(status));
 			ret = -1;
 			break;
 		}