message: add check for updateTokenAllowance
diff: @@ -1054,7 +1054,11 @@ class Exchange extends PureComponent<any, any> {
  maxAmount: 0,
  }
  }, () => {
  + const { isTokenSell, haveAmount } = this.state
  +
  + if (isTokenSell && haveAmount) {
  this.updateTokenAllowance()
  + }
  })
  }
  