Fix maprenderertest

By introducing some color tolerance

Author: m-kuhn

tests/src/core/testqgsmaprenderer.cpp

@@ -189,6 +189,7 @@ void TestQgsMapRenderer::performanceTest()
   myChecker.setControlName( "expected_maprender" );
   mMapSettings.setFlag( QgsMapSettings::Antialiasing );
   myChecker.setMapSettings( mMapSettings );
+  myChecker.setColorTolerance( 5 );
   bool myResultFlag = myChecker.runTest( "maprender" );
   mReport += myChecker.report();
   QVERIFY( myResultFlag );