fix ut.

Previously commit dont flush the over-written log,  and the log_entries
only look at flushed logs. As a result, the over-written log was
not included in the log_entries() result which breaks the UT.

The UT was running in master, because we dont at the over_written
entry into cache and the entry_at() call will inline flush this entry.
After adding it to cache it served from cache without flushing.

Signed-off-by: Xiaoxi Chen <[email protected]>

src/lib/replication/log_store/home_raft_log_store.cpp

@@ -190,6 +190,9 @@ void HomeRaftLogStore::write_at(ulong index, nuraft::ptr< nuraft::log_entry >& e
         std::unique_lock lk(m_mutex);
         m_log_entry_cache[position_in_cache] = std::make_pair(index, entry);
     }
+
+    // flushing the log before returning to ensure new(over-written) log is persisted to disk.
+    end_of_append_batch(index, 1);
 }
 
 void HomeRaftLogStore::end_of_append_batch(ulong start, ulong cnt) {