IECoreArnoldPreview : Remove unneeded error codes
IECoreArnoldPreview : Remove unneeded error codes

ivanimanishi/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,boberfly/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,GafferHQ/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,hradec/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,hradec/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,hradec/gaffer,lucienfostier/gaffer,hradec/gaffer,boberfly/gaffer,boberfly/gaffer,boberfly/gaffer,hradec/gaffer,lucienfostier/gaffer,ImageEngine/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer