src: Fix Memchunks move ctor

src/memchunk.h

@@ -90,7 +90,7 @@ template <typename Memchunk> struct Memchunks {
       : pool(pool), head(nullptr), tail(nullptr), len(0) {}
   Memchunks(const Memchunks &) = delete;
   Memchunks(Memchunks &&other)
-      : pool(other.pool), head(other.head), tail(other.head), len(other.len) {
+      : pool(other.pool), head(other.head), tail(other.tail), len(other.len) {
     // keep other.pool
     other.head = other.tail = nullptr;
     other.len = 0;