The halogen atom represented by A includes, for example, chlorine, bromine and fluorine atoms. [0026] A represents preferably a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms (e.g., methyl or ethyl), and particularly preferably a hydrogen atom or a methyl group. [0027] The halogen atom represented by R1 or R2 includes, for example, chlorine, bromine, fluorine and iodine atoms. [00