qml: don't show option Never for expiry combobox when in preferences

electrum/gui/qml/components/Preferences.qml

@@ -247,6 +247,7 @@ Pane {
                     }
 
                     RequestExpiryComboBox {
+                        includeNever: false
                         onCurrentValueChanged: {
                             if (activeFocus)
                                 Config.requestExpiry = currentValue

electrum/gui/qml/components/controls/RequestExpiryComboBox.qml

@@ -6,6 +6,8 @@ import org.electrum 1.0
 ElComboBox {
     id: expires
 
+    property bool includeNever: true
+
     textRole: 'text'
     valueRole: 'value'
 
@@ -18,7 +20,8 @@ ElComboBox {
             expiresmodel.append({'text': qsTr('1 day'), 'value': 24*60*60})
             expiresmodel.append({'text': qsTr('1 week'), 'value': 7*24*60*60})
             expiresmodel.append({'text': qsTr('1 month'), 'value': 31*24*60*60})
-            expiresmodel.append({'text': qsTr('Never'), 'value': 0})
+            if (includeNever)
+                expiresmodel.append({'text': qsTr('Never'), 'value': 0})
             expires.currentIndex = 0
             for (let i=0; i < expiresmodel.count; i++) {
                 if (expiresmodel.get(i).value == Config.requestExpiry) {