protocol: revert incoming chain height check against local chain

We can actually request a chain that's further away from what we
have as we buffer more and more

src/cryptonote_protocol/cryptonote_protocol_handler.inl

@@ -2491,7 +2491,7 @@ skip:
       drop_connection(context, true, false);
       return 1;
     }
-    if (arg.total_height < arg.m_block_ids.size() || arg.start_height > arg.total_height - arg.m_block_ids.size() || arg.start_height >= m_core.get_current_blockchain_height())
+    if (arg.total_height < arg.m_block_ids.size() || arg.start_height > arg.total_height - arg.m_block_ids.size())
     {
       LOG_ERROR_CCONTEXT("sent invalid start/nblocks/height, dropping connection");
       drop_connection(context, true, false);