[ksmserver] Drop multi X screen support

Summary:
We don't support multi X screen anymore in the rest of plasma. Cleans up
a bit of code.

Having multiple monitors via xrandr will still work as before.

Test Plan: Compiles

Reviewers: #plasma, apol

Reviewed By: apol

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D21757

ksmserver/main.cpp

@@ -324,16 +324,10 @@ extern "C" Q_DECL_EXPORT int kdemain( int argc, char* argv[] )
 
     KConfigGroup config(KSharedConfig::openConfig(), "General");
 
-    int realScreenCount = ScreenCount( QX11Info::display() );
-    bool screenCountChanged =
-         ( config.readEntry( "screenCount", realScreenCount ) != realScreenCount );
-
     QString loginMode = config.readEntry( "loginMode", "restorePreviousLogout" );
 
-    if ( parser.isSet( restoreOption ) && ! screenCountChanged )
+    if ( parser.isSet( restoreOption ))
         server->restoreSession( QStringLiteral( SESSION_BY_USER ) );
-    else if ( loginMode == QStringLiteral( "default" ) || screenCountChanged )
-        server->startDefaultSession();
     else if ( loginMode == QStringLiteral( "restorePreviousLogout" ) )
         server->restoreSession( QStringLiteral( SESSION_PREVIOUS_LOGOUT ) );
     else if ( loginMode == QStringLiteral( "restoreSavedSession" ) )

ksmserver/server.cpp

@@ -949,7 +949,6 @@ void KSMServer::storeSession()
     cg.writeEntry( "count", count );
 
     KConfigGroup cg2( config, "General");
-    cg2.writeEntry( "screenCount", ScreenCount(QX11Info::display()));
 
     storeLegacySession(config.data());
     config->sync();