srml-contracts: Deferred actions (#3255)

* Switch to deferred actions

* Make restore_to a deferred action.

* Bump version.

* Review fixes.

substrate/node/runtime/src/lib.rs

@@ -79,7 +79,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to equal spec_version. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 123,
+	spec_version: 125,
 	impl_version: 125,
 	apis: RUNTIME_API_VERSIONS,
 };