Log an error in rename_or_move() when there's a failure, for more debugging

details.

exec/binkit.js

@@ -324,10 +324,13 @@ function rename_or_move(src, dst)
 	if (file_rename(src, dst))
 		return true;
 	sf = new File(src);
-	if (!sf.open("rb"))
+	if (!sf.open("rb")) {
+		log(LOG_ERR, "Error " + sf.error + " opening " + sf.name);
 		return false;
+	}
 	df = new File(dst);
 	if (!df.open("wb")) {		// Used to include 'e' mode flag (which never worked)
+		log(LOG_ERR, "Error " + df.error + " opening " + df.name);
 		sf.close();
 		return false;
 	}
@@ -340,6 +343,7 @@ function rename_or_move(src, dst)
 			remain = 0x200000;
 		buf = sf.read(remain);
 		if (!df.write(buf)) {
+			log(LOG_ERR, "Error " + df.error + " writing to " + df.name);
 			df.close();
 			df.remove();
 			sf.close();