adds rpc error message for --no-ancient-blocks (#10608)

* adds error message for --no-ancient-blocks, closes #10261

* Apply suggestions from code review

Co-Authored-By: seunlanlege <seunlanlege@gmail.com>

parity/rpc_apis.rs

@@ -259,6 +259,7 @@ pub struct FullDependencies {
 	pub gas_price_percentile: usize,
 	pub poll_lifetime: u32,
 	pub allow_missing_blocks: bool,
+	pub no_ancient_blocks: bool,
 }
 
 impl FullDependencies {
@@ -310,6 +311,7 @@ impl FullDependencies {
 							gas_price_percentile: self.gas_price_percentile,
 							allow_missing_blocks: self.allow_missing_blocks,
 							allow_experimental_rpcs: self.experimental_rpcs,
+							no_ancient_blocks: self.no_ancient_blocks
 						}
 					);
 					handler.extend_with(client.to_delegate());

parity/run.rs

@@ -745,6 +745,7 @@ fn execute_impl<Cr, Rr>(cmd: RunCmd, logger: Arc<RotatingLogger>, on_client_rq:
 		gas_price_percentile: cmd.gas_price_percentile,
 		poll_lifetime: cmd.poll_lifetime,
 		allow_missing_blocks: cmd.allow_missing_blocks,
+		no_ancient_blocks: !cmd.download_old_blocks,
 	});
 
 	let dependencies = rpc::Dependencies {