Fix for relative blur size for non-fast gaussian blur methods.

Call base blur's initExecution from GaussianBokehBlurOperation and GaussianXBlurOperation

source/blender/compositor/operations/COM_GaussianBokehBlurOperation.cpp

@@ -43,6 +43,8 @@ void *GaussianBokehBlurOperation::initializeTileData(rcti *rect, MemoryBuffer **
 
 void GaussianBokehBlurOperation::initExecution()
 {
+	BlurBaseOperation::initExecution();
+
 	if (this->sizeavailable) {
 		updateGauss(NULL);
 	}

source/blender/compositor/operations/COM_GaussianXBlurOperation.cpp

@@ -45,6 +45,8 @@ void *GaussianXBlurOperation::initializeTileData(rcti *rect, MemoryBuffer **memo
 
 void GaussianXBlurOperation::initExecution()
 {
+	BlurBaseOperation::initExecution();
+
 	if (this->sizeavailable) {
 		float rad = size*this->data->sizex;
 		if (rad<1)