Bump rococo version (#2255)

* Add bad block to rococo

* Bump rococo spec_version

* Revert "Add bad block to rococo"

This reverts commit 56664ce36f4fd9ea570b63e7b6978a6d2ff2aace.

polkadot/runtime/rococo/src/lib.rs

@@ -100,7 +100,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("rococo"),
 	impl_name: create_runtime_str!("parity-rococo-v1"),
 	authoring_version: 0,
-	spec_version: 15,
+	spec_version: 17,
 	impl_version: 0,
 	#[cfg(not(feature = "disable-runtime-api"))]
 	apis: RUNTIME_API_VERSIONS,