Bump version to 2.5.1

Check the type of the returned error instead of the error message to
determine if the private key file is encrypted by a passphrase.

duplicacy/duplicacy_main.go

@@ -2084,7 +2084,7 @@ func main() {
 	app.Name = "duplicacy"
 	app.HelpName = "duplicacy"
 	app.Usage = "A new generation cloud backup tool based on lock-free deduplication"
-	app.Version = "2.5.0" + " (" + GitCommit + ")"
+	app.Version = "2.5.1" + " (" + GitCommit + ")"
 
 	// If the program is interrupted, call the RunAtError function.
 	c := make(chan os.Signal, 1)

src/duplicacy_storage.go

@@ -349,7 +349,7 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 				} else {
 					keySigner, err = ssh.ParsePrivateKey(content)
 					if err != nil {
-						if strings.Contains(err.Error(), "cannot decode encrypted private keys") {
+						if _, ok := err.(*ssh.PassphraseMissingError); ok {
 							LOG_TRACE("SSH_PUBLICKEY", "The private key file is encrypted")
 							passphrase = GetPassword(preference, "ssh_passphrase", "Enter the passphrase to decrypt the private key file:", false, resetPassword)
 							if len(passphrase) == 0 {