Change account.m_last_block_ptr in ForgetMRCRewardBlock to pindex from pindex->pprev
Change account.m_last_block_ptr in ForgetMRCRewardBlock to pindex from pindex->pprev

Co-authored-by: div72 <a70d82ac27b27c98947d4971a4c3f696537cc9cf@users.noreply.github.com>
caraka/gridcoinresearch,caraka/gridcoinresearch,caraka/gridcoinresearch,caraka/gridcoinresearch,caraka/gridcoinresearch,caraka/gridcoinresearch