copyFrom sets fork before creating batch

Author: chm-diederichs

lib/core.js

@@ -279,6 +279,8 @@ module.exports = class Core {
 
       await this.tree.flush()
 
+      this.tree.fork = fork
+
       let batch = this.tree.batch()
 
       // add additional blocks
@@ -334,9 +336,8 @@ module.exports = class Core {
 
       await batch.commit()
 
-      this.tree.fork = fork
-
       this.header.tree.length = this.tree.length
+      this.header.tree.fork = this.tree.fork
       this.header.tree.rootHash = this.tree.hash()
       this.header.tree.signature = this.tree.signature