contracts-bedrock: more fixup

packages/contracts-bedrock/scripts/Deploy.s.sol

@@ -387,7 +387,7 @@ contract Deploy is Deployer {
     function deploySystemConfig() broadcast() public returns (address) {
         SystemConfig config = new SystemConfig();
 
-        require(config.owner() == address(0));
+        require(config.owner() == address(0xdEaD));
         require(config.overhead() == 0);
         require(config.scalar() == 0);
         require(config.unsafeBlockSigner() == address(0));

packages/contracts-bedrock/src/L1/SystemConfig.sol

@@ -91,10 +91,12 @@ contract SystemConfig is OwnableUpgradeable, Semver {
     uint256 public startBlock;
 
     /// @custom:semver 1.4.0
-    /// @notice Constructs the SystemConfig contract.
+    /// @notice Constructs the SystemConfig contract. Cannot set
+    ///         the owner to `address(0)` due to the Ownable contract's
+    ///         implementation, so set it to `address(0xdEaD)`
     constructor() Semver(1, 4, 0) {
         initialize({
-            _owner: address(0),
+            _owner: address(0xdEaD),
             _overhead: 0,
             _scalar: 0,
             _batcherHash: bytes32(0),