ensure sealing work enabled if notifier registed

ethcore/src/miner/miner.rs

@@ -234,7 +234,8 @@ pub struct Miner {
 impl Miner {
 	/// Push notifier that will handle new jobs
 	pub fn push_notifier(&self, notifier: Box<NotifyWork>) {
-		self.notifiers.write().push(notifier)
+		self.notifiers.write().push(notifier);
+		self.sealing_work.lock().enabled = true;
 	}
 
 	/// Creates new instance of miner Arc.

ethcore/src/miner/stratum.rs

@@ -211,6 +211,8 @@ impl From<AddrParseError> for Error {
 
 impl super::work_notify::NotifyWork for Stratum {
 	fn notify(&self, pow_hash: H256, difficulty: U256, number: u64) {
+		trace!(target: "stratum", "Notify work");
+
 		self.service.push_work_all(
 			self.dispatcher.payload(pow_hash, difficulty, number)
 		).unwrap_or_else(