Revert "don't respond to MEMPOOL req"
Revert "don't respond to MEMPOOL req"

This reverts commit 23385a56ff213ea683e083b6bab89fd8e9356702 [formerly d8f460f7857caba2ffe779ee4d4492cdacab217a].


Former-commit-id: aeb3b0fdc031f3dfd6dcde7891b662afc7d3e649
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin