remove nMVFDefaultActivateForkHeight, use HARDFORK_RETARGET_BLOCKS, further sync to MVF-BU
remove nMVFDefaultActivateForkHeight, use HARDFORK_RETARGET_BLOCKS, further sync to MVF-BU
BTCfork/hardfork_prototype_1_mvf-core,BTCfork/hardfork_prototype_1_mvf-core,BTCfork/hardfork_prototype_1_mvf-core,BTCfork/hardfork_prototype_1_mvf-core,BTCfork/hardfork_prototype_1_mvf-core,BTCfork/hardfork_prototype_1_mvf-core