Don't try to load translations for C locale

src/lib/app/mainapplication.cpp

@@ -970,9 +970,12 @@ void MainApplication::translateApp()
 {
     QString file = Settings().value(QSL("Language/language"), QLocale::system().name()).toString();
 
-    if (!file.isEmpty() && !file.endsWith(QL1S(".qm"))) {
+    // It can only be "C" locale, for which we will use default English language
+    if (file.size() < 2)
+        file.clear();
+
+    if (!file.isEmpty() && !file.endsWith(QL1S(".qm")))
         file.append(QL1S(".qm"));
-    }
 
     // Either we load default language (with empty file), or we attempt to load xx.qm (xx_yy.qm)
     Q_ASSERT(file.isEmpty() || file.size() >= 5);