Turn TryCreateDirectory() into TryCreateDirectories()

Use case: TryCreateDirectory(GetDataDir() / "blocks" / "index") would
fail if the blocks directory was not explicitly created before.

The line that did so was in a weird location and could be removed as a
result.

src/init.cpp

@@ -1410,8 +1410,6 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
     fReindex = GetBoolArg("-reindex", false);
     bool fReindexChainState = GetBoolArg("-reindex-chainstate", false);
 
-    fs::create_directories(GetDataDir() / "blocks");
-
     // cache size calculations
     int64_t nTotalCache = (GetArg("-dbcache", nDefaultDbCache) << 20);
     nTotalCache = std::max(nTotalCache, nMinDbCache << 20); // total cache cannot be less than nMinDbCache