Gas: Unnecessary assignment in SavingsAccount.withdrawAll

[code423n4]

Handle

cmichel

Vulnerability details

The function computes uint256 _amount = balanceInShares[msg.sender][_token][_strategyList[i]]; but this value is never used and reassigned in the next line to _amount = IYield(_strategyList[i]).unlockTokens(_token, balanceInShares[msg.sender][_token][_strategyList[i]]);.
The first line can therefore be removed.

[ritik99]

Duplicate of #36 since both issues deal with unnecessary initializations. Hence, the issue is the same even if the instances mentioned in both the places are different