fix wrong None return result after eval in changeAttrExpression
fix wrong None return result after eval in changeAttrExpression

fabioz/PyDev.Debugger,Elizaveta239/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,fabioz/PyDev.Debugger,simudream/PyDev.Debugger,Elizaveta239/PyDev.Debugger,fabioz/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,simudream/PyDev.Debugger,SylvainCorlay/PyDev.Debugger,Elizaveta239/PyDev.Debugger,Elizaveta239/PyDev.Debugger,fabioz/PyDev.Debugger,fabioz/PyDev.Debugger,simudream/PyDev.Debugger,simudream/PyDev.Debugger,Elizaveta239/PyDev.Debugger,SylvainCorlay/PyDev.Debugger