[parser] remove unnecessary variable (#655)
[parser] remove unnecessary variable (#655)


coocood/tidb,kyle-wang/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,coocood/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb