Move DEFAULT_PERSIST_MEMPOOL out of libbitcoinkernel

It is no longer used by anything inside libbitcoinkernel, move it to
node/mempool_persist_args.h where it belongs.

src/init.cpp

@@ -109,6 +109,7 @@ using node::CalculateCacheSizes;
 using node::ChainstateLoadVerifyError;
 using node::ChainstateLoadingError;
 using node::CleanupBlockRevFiles;
+using node::DEFAULT_PERSIST_MEMPOOL;
 using node::DEFAULT_PRINTPRIORITY;
 using node::DEFAULT_STOPAFTERBLOCKIMPORT;
 using node::LoadChainstate;

src/node/mempool_persist_args.h

@@ -11,6 +11,12 @@ class ArgsManager;
 
 namespace node {
 
+/**
+ * Default for -persistmempool, indicating whether the node should attempt to
+ * automatically load the mempool on start and save to disk on shutdown
+ */
+static constexpr bool DEFAULT_PERSIST_MEMPOOL{true};
+
 bool ShouldPersistMempool(const ArgsManager& argsman);
 fs::path MempoolPath(const ArgsManager& argsman);
 

src/validation.h

@@ -68,8 +68,6 @@ static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
 static constexpr bool DEFAULT_COINSTATSINDEX{false};
 static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
-/** Default for -persistmempool */
-static const bool DEFAULT_PERSIST_MEMPOOL = true;
 /** Default for -stopatheight */
 static const int DEFAULT_STOPATHEIGHT = 0;
 /** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of ActiveChain().Tip() will not be pruned. */