[test] rename SegwitVersion1SignatureHash()

The function implementing segwit v0 signature hash was originally named
SegwitVersion1SignatureHash() (presumably before segwit v0 was named
segwit v0). Rename it to SegwitV0SignatureHash().

Also rename SignatureHash() to LegacySignatureHash() for disambiguation.

test/functional/p2p_segwit.py

@@ -67,8 +67,8 @@ from test_framework.script import (
     SIGHASH_ANYONECANPAY,
     SIGHASH_NONE,
     SIGHASH_SINGLE,
-    SegwitVersion1SignatureHash,
-    SignatureHash,
+    SegwitV0SignatureHash,
+    LegacySignatureHash,
     hash160,
 )
 from test_framework.test_framework import BitcoinTestFramework
@@ -103,7 +103,7 @@ def get_p2pkh_script(pubkeyhash):
 
 def sign_p2pk_witness_input(script, tx_to, in_idx, hashtype, value, key):
     """Add signature for a P2PK witness program."""
-    tx_hash = SegwitVersion1SignatureHash(script, tx_to, in_idx, hashtype, value)
+    tx_hash = SegwitV0SignatureHash(script, tx_to, in_idx, hashtype, value)
     signature = key.sign_ecdsa(tx_hash) + chr(hashtype).encode('latin-1')
     tx_to.wit.vtxinwit[in_idx].scriptWitness.stack = [signature, script]
     tx_to.rehash()
@@ -1489,7 +1489,7 @@ class SegWitTest(BitcoinTestFramework):
         tx2.vin.append(CTxIn(COutPoint(tx.sha256, 0), b""))
         tx2.vout.append(CTxOut(tx.vout[0].nValue - 1000, script_wsh))
         script = get_p2pkh_script(pubkeyhash)
-        sig_hash = SegwitVersion1SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
+        sig_hash = SegwitV0SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
         signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
         tx2.wit.vtxinwit.append(CTxInWitness())
         tx2.wit.vtxinwit[0].scriptWitness.stack = [signature, pubkey]
@@ -1543,7 +1543,7 @@ class SegWitTest(BitcoinTestFramework):
         tx5 = CTransaction()
         tx5.vin.append(CTxIn(COutPoint(tx4.sha256, 0), b""))
         tx5.vout.append(CTxOut(tx4.vout[0].nValue - 1000, CScript([OP_TRUE])))
-        (sig_hash, err) = SignatureHash(script_pubkey, tx5, 0, SIGHASH_ALL)
+        (sig_hash, err) = LegacySignatureHash(script_pubkey, tx5, 0, SIGHASH_ALL)
         signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
         tx5.vin[0].scriptSig = CScript([signature, pubkey])
         tx5.rehash()
@@ -1693,7 +1693,7 @@ class SegWitTest(BitcoinTestFramework):
         tx2.vout.append(CTxOut(tx.vout[0].nValue, CScript([OP_TRUE])))
 
         script = get_p2pkh_script(pubkeyhash)
-        sig_hash = SegwitVersion1SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
+        sig_hash = SegwitV0SignatureHash(script, tx2, 0, SIGHASH_ALL, tx.vout[0].nValue)
         signature = key.sign_ecdsa(sig_hash) + b'\x01'  # 0x1 is SIGHASH_ALL
 
         # Check that we can't have a scriptSig