JobQueue::AddJob() returns error on lock failure.

* If the lock could not be obtained, it will now return B_ERROR
  instead of B_OK.

src/kits/support/JobQueue.cpp

@@ -84,7 +84,9 @@ JobQueue::AddJob(BJob* job)
 		return B_NO_INIT;
 
 	BAutolock lock(&fLock);
-	if (lock.IsLocked()) {
+	if (!lock.IsLocked())
+		return B_ERROR;
+
 	try {
 		if (!fQueuedJobs->insert(job).second)
 			return B_NAME_IN_USE;
@@ -97,7 +99,6 @@ JobQueue::AddJob(BJob* job)
 	job->AddStateListener(this);
 	if (job->IsRunnable())
 		release_sem(fHaveRunnableJobSem);
-	}
 
 	return B_OK;
 }