[calamares] Remove intermediate debug-settings

- There's a multi-stage setup for debug-mode, where the application
   object also knows that debugging is set. Remove it.
 - Break debug mode (because now the settings don't get debug-mode set).
 - Refactor so that parameter handing is only done if this Calamares
   is the unique (first) Calamares.

src/calamares/CalamaresApplication.cpp

@@ -42,12 +42,17 @@
 #include <QScreen>
 #include <QTimer>
 
+/// @brief Convenience for "are the settings in debug mode"
+static bool
+isDebug()
+{
+    return Calamares::Settings::instance() && Calamares::Settings::instance()->debugMode();
+}
 
 CalamaresApplication::CalamaresApplication( int& argc, char* argv[] )
     : QApplication( argc, argv )
     , m_mainwindow( nullptr )
     , m_moduleManager( nullptr )
-    , m_debugMode( false )
 {
     // Setting the organization name makes the default cache
     // directory -- where Calamares stores logs, for instance --
@@ -102,20 +107,6 @@ CalamaresApplication::instance()
 }
 
 
-void
-CalamaresApplication::setDebug( bool enabled )
-{
-    m_debugMode = enabled;
-}
-
-
-bool
-CalamaresApplication::isDebug()
-{
-    return m_debugMode;
-}
-
-
 CalamaresWindow*
 CalamaresApplication::mainWindow()
 {

src/calamares/CalamaresApplication.h

@@ -49,16 +49,6 @@ public:
     void init();
     static CalamaresApplication* instance();
 
-    /**
-     * @brief setDebug controls whether debug mode is enabled
-     */
-    void setDebug( bool enabled );
-
-    /**
-     * @brief isDebug returns true if running in debug mode, otherwise false.
-     */
-    bool isDebug();
-
     /**
      * @brief mainWindow returns the Calamares application main window.
      */
@@ -78,8 +68,6 @@ private:
 
     CalamaresWindow* m_mainwindow;
     Calamares::ModuleManager* m_moduleManager;
-
-    bool m_debugMode;
 };
 
 #endif  // CALAMARESAPPLICATION_H

src/calamares/main.cpp

@@ -73,8 +73,7 @@ handle_args( CalamaresApplication& a )
 
     parser.process( a );
 
-    a.setDebug( parser.isSet( debugOption ) );
+    Logger::setupLogLevel( parser.isSet( debugOption ) ? Logger::LOGVERBOSE : debug_level( parser, debugLevelOption ) );
-    Logger::setupLogLevel( a.isDebug() ? Logger::LOGVERBOSE : debug_level( parser, debugLevelOption ) );
     if ( parser.isSet( configOption ) )
     {
         CalamaresUtils::setAppDataDir( QDir( parser.value( configOption ) ) );
@@ -83,6 +82,8 @@ handle_args( CalamaresApplication& a )
     {
         CalamaresUtils::setXdgDirs();
     }
+
+    a.init();
 }
 
 int
@@ -110,11 +111,10 @@ main( int argc, char* argv[] )
     // TODO: umount anything in /tmp/calamares-... as an emergency save function
 #endif
 
-    handle_args( a );
     KDSingleApplicationGuard guard( KDSingleApplicationGuard::AutoKillOtherInstances );
     if ( guard.isPrimaryInstance() )
     {
-        a.init();
+        handle_args( a );
         return a.exec();
     }
     else