[kstyle] Fix deprecation warnings

Summary: See https://build.kde.org/job/Plasma%20breeze%20kf5-qt5%20FreeBSDQt5.11/4/warnings12Result/

Test Plan: Compiles.

Reviewers: #plasma, broulik

Reviewed By: #plasma, broulik

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D15285

kstyle/breezestyle.cpp

@@ -3744,7 +3744,11 @@ namespace Breeze
 
         const bool hasCustomBackground = viewItemOption->backgroundBrush.style() != Qt::NoBrush && !( state & State_Selected );
         const bool hasSolidBackground = !hasCustomBackground || viewItemOption->backgroundBrush.style() == Qt::SolidPattern;
+        #if BREEZE_USE_KDE4
         const bool hasAlternateBackground( viewItemOption->features & QStyleOptionViewItemV2::Alternate );
+        #else
+        const bool hasAlternateBackground( viewItemOption->features & QStyleOptionViewItem::Alternate );
+        #endif
 
         // do nothing if no background is to be rendered
         if( !( mouseOver || selected || hasCustomBackground || hasAlternateBackground ) )
@@ -3756,7 +3760,7 @@ namespace Breeze
         else colorGroup = QPalette::Disabled;
 
         // render alternate background
-        if( viewItemOption && ( viewItemOption->features & QStyleOptionViewItemV2::Alternate ) )
+        if( hasAlternateBackground )
         {
             painter->setPen( Qt::NoPen );
             painter->setBrush( palette.brush( colorGroup, QPalette::AlternateBase ) );

kstyle/breezewindowmanager.cpp

@@ -758,7 +758,11 @@ namespace Breeze
             // gather options to retrieve checkbox subcontrol rect
             QStyleOptionGroupBox opt;
             opt.initFrom( groupBox );
+            #if BREEZE_USE_KDE4
             if( groupBox->isFlat() ) opt.features |= QStyleOptionFrameV2::Flat;
+            #else
+            if( groupBox->isFlat() ) opt.features |= QStyleOptionFrame::Flat;
+            #endif
             opt.lineWidth = 1;
             opt.midLineWidth = 0;
             opt.text = groupBox->title();