XMozToken cannot be added to its own whitelist
By design, XMozToken should always be in the whitelist. However, `updateTransferWhitelist()` implementation forbids both removal and insertion of XMozToken to the whitelist.\\n```\\n            function updateTransferWhitelist(address account, bool add) external  onlyMultiSigAdmin {\\n                    require(account != address(this), "updateTransferWhitelist: \\n                          Cannot remove xMoz from whitelist");\\n                    if(add) _transferWhitelist.add(account);\\n                 else _transferWhitelist.remove(account);\\n            emit SetTransferWhitelist(account, add);\\n            }\\n```\\n
Move the require statement into the else clause.
```\\n            function updateTransferWhitelist(address account, bool add) external  onlyMultiSigAdmin {\\n                    require(account != address(this), "updateTransferWhitelist: \\n                          Cannot remove xMoz from whitelist");\\n                    if(add) _transferWhitelist.add(account);\\n                 else _transferWhitelist.remove(account);\\n            emit SetTransferWhitelist(account, add);\\n            }\\n```\\n