idletime: fix another missing unlock on error

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/idletime.c b/idletime.c
index 8d23154..a366d2b 100644
--- a/idletime.c
+++ b/idletime.c
@@ -73,8 +73,10 @@
 	pthread_mutex_lock(&ipt->init_lock);
 
 	/* exit if any other thread failed to start */
-	if (ipc.status == IDLE_PROF_STATUS_ABORT)
+	if (ipc.status == IDLE_PROF_STATUS_ABORT) {
+		pthread_mutex_unlock(&ipt->init_lock);
 		return NULL;
+	}
 
 	retval = set_cpu_affinity(ipt);
 	if (retval == -1) {