Uninitialized state variable detector: remove FP due to delegatecall proxy

[montyly]

Fix #178

[montyly]

Example:

// Do not use this code, it is buggy

contract Initializable{}

contract C is Initializable{

    address owner;

    function use_owner() public {
        require(owner == msg.sender);
    }

}

contract Proxy{

    address owner = msg.sender;

    function () external{
        assembly{
            let ret := delegatecall(
                    0,                
                    0,           
                    0,    
                    0,        
                    0,                 
                    0                   
                )
        }
    }

}

C.owner is correctly not detected as an uninitialized variable