Remove initialize from ERC721Full

Following d75ba162 ERC721 should not initialize their parents.

contracts/token/ERC721/ERC721Full.sol

@@ -12,9 +12,5 @@ import "./ERC721Metadata.sol";
  * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
  */
 contract ERC721Full is Initializable, ERC721, ERC721Enumerable, ERC721Metadata {
-    function initialize(string memory name, string memory symbol) public initializer {
-      ERC721Metadata.initialize(name, symbol);
-    }
-
     uint256[50] private ______gap;
 }