[hotfix] Fix AbstractKeyedCEPPatternOperator.restoreState()

Before, this was trying to cast the StreamTaskState directly to a
StateHandle<DataInputView> while it should take the operator state, i.e:

StateHandle<DataInputView> stateHandle =
  (StateHandle<DataInputView>) state.getOperatorState();

flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/operator/AbstractKeyedCEPPatternOperator.java

@@ -190,7 +190,7 @@ abstract public class AbstractKeyedCEPPatternOperator<IN, KEY, OUT> extends Abst
 		super.restoreState(state, recoveryTimestamp);
 
 		@SuppressWarnings("unchecked")
-		StateHandle<DataInputView> stateHandle = (StateHandle<DataInputView>) state;
+		StateHandle<DataInputView> stateHandle = (StateHandle<DataInputView>) state.getOperatorState();
 
 		DataInputView inputView = stateHandle.getState(getUserCodeClassloader());