Merge bitcoin#8041: [qa] Fix bip9-softforks blockstore issue

fad60b3 [qa] Fix bip9-softforks blockstore issue (MarcoFalke)

qa/rpc-tests/bip9-softforks.py

@@ -3,6 +3,7 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+from test_framework.blockstore import BlockStore
 from test_framework.test_framework import ComparisonTestFramework
 from test_framework.util import *
 from test_framework.mininode import CTransaction, NetworkThread
@@ -192,11 +193,13 @@ def test_BIP(self, bipName, activated_version, invalidate, invalidatePostSignatu
         yield TestInstance([[block, False]])
 
         # Restart all
+        self.test.block_store.close()
         stop_nodes(self.nodes)
         wait_bitcoinds()
         shutil.rmtree(self.options.tmpdir)
         self.setup_chain()
         self.setup_network()
+        self.test.block_store = BlockStore(self.options.tmpdir)
         self.test.clear_all_connections()
         self.test.add_all_connections(self.nodes)
         NetworkThread().start() # Start up network handling in another thread