qt, wallet: Drop unused parameter in WalletModel::setWalletEncrypted

Summary:
This is a backport of [[bitcoin-core/gui#109 | core-gui#109]] [3/3]
bitcoin-core/gui@4146a31

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10739

Author: hebasto

src/qt/askpassphrasedialog.cpp

@@ -129,7 +129,7 @@ void AskPassphraseDialog::accept() {
                                 encryption_reminder + "</b></qt>");
                     } else {
                         assert(model != nullptr);
-                        if (model->setWalletEncrypted(true, newpass1)) {
+                        if (model->setWalletEncrypted(newpass1)) {
                             QMessageBox::warning(
                                 this, tr("Wallet encrypted"),
                                 "<qt>" + tr("Your wallet is now encrypted. ") +

src/qt/walletmodel.cpp

@@ -338,12 +338,8 @@ WalletModel::EncryptionStatus WalletModel::getEncryptionStatus() const {
     }
 }
 
-bool WalletModel::setWalletEncrypted(bool encrypted,
-                                     const SecureString &passphrase) {
-    if (encrypted) {
-        return m_wallet->encryptWallet(passphrase);
-    }
-    return false;
+bool WalletModel::setWalletEncrypted(const SecureString &passphrase) {
+    return m_wallet->encryptWallet(passphrase);
 }
 
 bool WalletModel::setWalletLocked(bool locked, const SecureString &passPhrase) {

src/qt/walletmodel.h

@@ -104,7 +104,7 @@ class WalletModel : public QObject {
     SendCoinsReturn sendCoins(WalletModelTransaction &transaction);
 
     // Wallet encryption
-    bool setWalletEncrypted(bool encrypted, const SecureString &passphrase);
+    bool setWalletEncrypted(const SecureString &passphrase);
     // Passphrase only needed when unlocking
     bool setWalletLocked(bool locked,
                          const SecureString &passPhrase = SecureString());