[Storage][Pruner] Fix pruning pending check
[Storage][Pruner] Fix pruning pending check

Closes: #490

aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core