devicemodel: do not lock when emitting signal

This can cause a deadlock, also use onAccepted to avoid
sporadic changes

Change-Id: Ic7ff97b7e8fdd64da981eaf0b3148edd6d4eccd6
GitLab: #1011

src/app/settingsview/components/DeviceItemDelegate.qml

@@ -89,7 +89,7 @@ ItemDelegate {
                 loseFocusWhenEnterPressed: true
                 backgroundColor: JamiTheme.transparentColor
 
-                onEditingFinished: {
+                onAccepted: {
                     AvAdapter.setDeviceName(editDeviceName.text)
                     editable = !editable
                 }

src/libclient/devicemodel.cpp

@@ -105,12 +105,12 @@ DeviceModel::setCurrentDeviceName(const QString& newName)
     config.deviceName = newName;
     owner.accountModel->setAccountConfig(owner.id, config);
     // Update model
-    std::lock_guard<std::mutex> lock(pimpl_->devicesMtx_);
+    std::unique_lock<std::mutex> lock(pimpl_->devicesMtx_);
     for (auto& device : pimpl_->devices_) {
         if (device.id == config.deviceId) {
             device.name = newName;
+            lock.unlock();
             Q_EMIT deviceUpdated(device.id);
-
             return;
         }
     }