log: improve some validation log messages to include hashPrevBlock

When there is an issue with a previous block the current log messages do
not indicate hashPrevBlock. Adding it makes debugging easier.

Author: sdulfari

src/validation.cpp

@@ -3676,12 +3676,12 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
         CBlockIndex* pindexPrev = nullptr;
         BlockMap::iterator mi{m_blockman.m_block_index.find(block.hashPrevBlock)};
         if (mi == m_blockman.m_block_index.end()) {
-            LogPrint(BCLog::VALIDATION, "%s: %s prev block not found\n", __func__, hash.ToString());
+            LogPrint(BCLog::VALIDATION, "header %s has prev block not found: %s\n", hash.ToString(), block.hashPrevBlock.ToString());
             return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV, "prev-blk-not-found");
         }
         pindexPrev = &((*mi).second);
         if (pindexPrev->nStatus & BLOCK_FAILED_MASK) {
-            LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString());
+            LogPrint(BCLog::VALIDATION, "header %s has prev block invalid: %s\n", hash.ToString(), block.hashPrevBlock.ToString());
             return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk");
         }
         if (!ContextualCheckBlockHeader(block, state, m_blockman, *this, pindexPrev, m_options.adjusted_time_callback())) {
@@ -3722,7 +3722,7 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
                         m_blockman.m_dirty_blockindex.insert(invalid_walk);
                         invalid_walk = invalid_walk->pprev;
                     }
-                    LogPrint(BCLog::VALIDATION, "%s: %s prev block invalid\n", __func__, hash.ToString());
+                    LogPrint(BCLog::VALIDATION, "header %s has prev block invalid: %s\n", hash.ToString(), block.hashPrevBlock.ToString());
                     return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk");
                 }
             }