[locale] Replace weird static-constructor

- Replace createDefault() with a constructor that takes a
   locale name; use it with en_US.UTF-8 in those places where
   createDefault was previously used.

src/modules/locale/LocaleConfiguration.cpp

@@ -27,14 +27,12 @@ LocaleConfiguration::LocaleConfiguration()
 }
 
 
-LocaleConfiguration
-LocaleConfiguration::createDefault()
+LocaleConfiguration::LocaleConfiguration( const QString& localeName )
+    : LocaleConfiguration()
 {
-    LocaleConfiguration lc = LocaleConfiguration();
-    lc.lang = lc.lc_numeric = lc.lc_time = lc.lc_monetary = lc.lc_paper = lc.lc_name
-            = lc.lc_address = lc.lc_telephone = lc.lc_measurement
-            = lc.lc_identification = "en_US.UTF-8";
-    return lc;
+    lang = lc_numeric = lc_time = lc_monetary = lc_paper = lc_name
+            = lc_address = lc_telephone = lc_measurement
+            = lc_identification = localeName;
 }
 
 

src/modules/locale/LocaleConfiguration.h

@@ -26,9 +26,11 @@
 class LocaleConfiguration
 {
 public:
+    /// @brief Create an empty locale, with nothing set
     explicit LocaleConfiguration();
+    /// @brief Create a locale with everything set to the given @p localeName
+    explicit LocaleConfiguration( const QString& localeName /* "en_US.UTF-8" */ );
 
-    static LocaleConfiguration createDefault();
     static LocaleConfiguration fromLanguageAndLocation( const QString& language,
                                                         const QStringList& availableLocales,
                                                         const QString& countryCode );

src/modules/locale/LocalePage.cpp

@@ -452,18 +452,20 @@ LocalePage::onActivate()
 LocaleConfiguration
 LocalePage::guessLocaleConfiguration() const
 {
+    static QString defaultLocale = QStringLiteral( "en_US.UTF-8" );
+
     QLocale myLocale;   // User-selected language
 
     // If we cannot say anything about available locales
     if ( m_localeGenLines.isEmpty() )
     {
         cWarning() << "guessLocaleConfiguration can't guess from an empty list.";
-        return LocaleConfiguration::createDefault();
+        return LocaleConfiguration( defaultLocale );
     }
 
     QString myLanguageLocale = myLocale.name();
     if ( myLanguageLocale.isEmpty() )
-        return LocaleConfiguration::createDefault();
+        return LocaleConfiguration( defaultLocale );
 
     return LocaleConfiguration::fromLanguageAndLocation( myLanguageLocale,
                                                          m_localeGenLines,