Remove InherentsPool and introduce non-propagateable transactions. (#2695)

* Remove InherentsPool.

* Introduce transactions that are not propagated over the network.

* Bump spec version.

* Use separate flag for propagation.

* Fix tests.

substrate/node/cli/src/service.rs

@@ -87,7 +87,6 @@ construct_service_factory! {
 					let proposer = Arc::new(substrate_basic_authorship::ProposerFactory {
 						client: service.client(),
 						transaction_pool: service.transaction_pool(),
-						inherents_pool: service.inherents_pool(),
 					});
 
 					let client = service.client();