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

test/functional/p2p_segwit.py

@@ -232,7 +232,6 @@ class SegWitTest(BitcoinTestFramework):
         height = self.nodes[0].getblockcount() + 1
         block_time = self.nodes[0].getblockheader(tip)["mediantime"] + 1
         block = create_block(int(tip, 16), create_coinbase(height), block_time)
-        block.nVersion = 4
         block.rehash()
         return block