mvcc: Add Unlock before panic to prevent double lock

mvcc/kvstore.go

@@ -427,6 +427,7 @@ func (s *store) restore() error {
 
 	for key, lid := range keyToLease {
 		if s.le == nil {
+			tx.Unlock()
 			panic("no lessor to attach lease")
 		}
 		err := s.le.Attach(lid, []lease.LeaseItem{{Key: key}})

mvcc/watchable_store.go

@@ -159,6 +159,7 @@ func (s *watchableStore) cancelWatcher(wa *watcher) {
 		}
 
 		if !wa.victim {
+			s.mu.Unlock()
 			panic("watcher not victim but not in watch groups")
 		}