ERC20 implementation has extraneous quantity check

[fulldecent]

The code:

  function _burn(address account, uint256 value) internal {
    require(account != 0);
    require(value <= _balances[account]);

    _totalSupply = _totalSupply.sub(value);
    _balances[account] = _balances[account].sub(value);
    emit Transfer(account, address(0), value);
  }

From:

https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC20/ERC20.sol#L186-L193

Has an unnecessary require(value <= _balances[account]); This test is already performed as part of the following line _balances[account] = _balances[account].sub(value);.

Likewise for burnFrom.

[Aniket-Engg]

If that is a case, i think it also applies for _transfer & transferFrom