fixes

Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>

Author: dranikpg

src/server/tiering/op_manager.cc

@@ -107,6 +107,7 @@ std::error_code OpManager::PrepareAndStash(EntryId id, size_t length,
 
   size_t written = writer(buf->second.bytes);
   Stash(id, {buf->first, written}, buf->second);
+  return {};
 }
 
 OpManager::ReadOp& OpManager::PrepareRead(DiskSegment aligned_segment) {

src/server/tiering/serialized_map_test.cc

@@ -31,6 +31,7 @@ TEST_F(SerializedMapTest, TestBasic) {
   auto lw = detail::ListpackWrap::WithCapacity(100);
   for (const auto& [k, v] : kBase)
     lw.Insert(k, v, false);
+  lw.GetPointer();  // to mark as non dirty // TODO: remove
 
   // Serialize kBase to buffer
   std::string buffer;