Fixed the background of the icon in the search input

It was opaque, whereas now it adapts better with varying background
colors.

src/plugins/find/findtoolbar.cpp

@@ -460,8 +460,8 @@ void FindToolBar::updateIcons()
     bool wholewords = effectiveFlags & IFindSupport::FindWholeWords;
     bool regexp = effectiveFlags & IFindSupport::FindRegularExpression;
     QPixmap pixmap(17, 17);
+    pixmap.fill(Qt::transparent);
     QPainter painter(&pixmap);
-    painter.eraseRect(0, 0, 17, 17);
     int x = 16;
 
     if (casesensitive) {