Handle blank passwords/cancel.

Fixes #10

src/controller.cpp

@@ -462,6 +462,9 @@ void Controller::unlockIfEncrypted(std::function<void(void)> cb, std::function<v
         zrpc->unlockWallet(password, [=](json reply) {
             if (isJsonSuccess(reply)) {
                 cb();
+
+                // Refresh the wallet so the encryption status is now in sync.
+                refresh(true);
             } else {
                 QMessageBox::critical(main, main->tr("Wallet Decryption Failed"),
                     QString::fromStdString(reply["error"].get<json::string_t>()),

src/mainwindow.cpp

@@ -296,8 +296,22 @@ void MainWindow::removeWalletEncryption() {
         return;
     }
 
+    bool ok;
     QString password = QInputDialog::getText(this, tr("Wallet Password"), 
-                            tr("Please enter your wallet password"), QLineEdit::Password);
+                            tr("Please enter your wallet password"), QLineEdit::Password, "", &ok);
+
+    // If cancel was pressed, just return
+    if (!ok) {
+        return;
+    }
+
+    if (password.isEmpty()) {
+        QMessageBox::critical(this, tr("Wallet Decryption Failed"),
+            tr("Please enter a password to decrypt your wallet!"),
+            QMessageBox::Ok
+        );
+        return;
+    }
 
     rpc->removeWalletEncryption(password, [=] (json res) {
         if (isJsonSuccess(res)) {