Add hasKey property to database and also make it accessible via the DatabaseWidget.

src/gui/DatabaseWidget.cpp

@@ -161,7 +161,7 @@ void DatabaseWidget::updateMasterKey(bool accepted)
         m_db->setKey(m_changeMasterKeyWidget->newMasterKey());
 
     }
-    else if (m_db->transformedMasterKey().isEmpty()) { // TODO other test?
+    else if (m_db->hasKey()) {
         Q_EMIT closeRequest();
         return;
     }
@@ -184,3 +184,8 @@ void DatabaseWidget::switchToMasterKeyChange()
     m_changeMasterKeyWidget->clearForms();
     setCurrentIndex(3);
 }
+
+bool DatabaseWidget::dbHasKey()
+{
+    return m_db->hasKey();
+}