init: start indexes sync earlier

The mempool load can take a while, and it is not
needed for the indexes' synchronization.

Also, having the mempool load function call
inside 'blockstorage.cpp' wasn't structurally
correct.

src/init.cpp

@@ -1657,7 +1657,10 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     }
 
     chainman.m_load_block = std::thread(&util::TraceThread, "loadblk", [=, &chainman, &args] {
-        ThreadImport(chainman, vImportFiles, ShouldPersistMempool(args) ? MempoolPath(args) : fs::path{});
+        // Import blocks
+        ThreadImport(chainman, vImportFiles);
+        // Load mempool from disk
+        chainman.ActiveChainstate().LoadMempool(ShouldPersistMempool(args) ? MempoolPath(args) : fs::path{});
     });
 
     // Wait for genesis block to be processed

src/node/blockstorage.cpp

@@ -868,7 +868,7 @@ public:
     }
 };
 
-void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFiles, const fs::path& mempool_path)
+void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFiles)
 {
     ScheduleBatchPriority();
 
@@ -939,7 +939,7 @@ void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFile
             return;
         }
     } // End scope of ImportingNow
-    chainman.ActiveChainstate().LoadMempool(mempool_path);
+
     g_indexes_ready_to_sync = true;
 }
 } // namespace node

src/node/blockstorage.h

@@ -255,7 +255,7 @@ public:
     void CleanupBlockRevFiles() const;
 };
 
-void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFiles, const fs::path& mempool_path);
+void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFiles);
 } // namespace node
 
 #endif // BITCOIN_NODE_BLOCKSTORAGE_H