test: refactor: take use of create_block version parameter (or use default)

test/functional/feature_versionbits_warning.py

@@ -48,8 +48,7 @@ class VersionBitsWarningTest(BitcoinTestFramework):
         tip = int(tip, 16)
 
         for _ in range(numblocks):
-            block = create_block(tip, create_coinbase(height + 1), block_time)
-            block.nVersion = version
+            block = create_block(tip, create_coinbase(height + 1), block_time, version=version)
             block.solve()
             peer.send_message(msg_block(block))
             block_time += 1