BUG/MAJOR: threads/checks: wrong use of SPIN_LOCK instead of SPIN_UNLOCK

Must unlock on exit, copy-paste error.
diff --git a/src/checks.c b/src/checks.c
index 3c2eeb6..222704a 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -2091,7 +2091,7 @@
  reschedule:
 	while (tick_is_expired(t->expire, now_ms))
 		t->expire = tick_add(t->expire, MS_TO_TICKS(check->inter));
-	SPIN_LOCK(SERVER_LOCK, &check->server->lock);
+	SPIN_UNLOCK(SERVER_LOCK, &check->server->lock);
 	return t;
 }