[qa] py2: Unfiddle strings into bytes explicitly

Github-Pull: #7853
Rebased-From: faa41ee204, fa7abe0a00

 Conflicts:
	qa/rpc-tests/invalidtxrequest.py
	qa/rpc-tests/p2p-feefilter.py
	qa/rpc-tests/proxy_test.py
	qa/rpc-tests/test_framework/mininode.py
	qa/rpc-tests/test_framework/netutil.py
	src/test/bctest.py

qa/rpc-tests/test_framework/util.py

@@ -1,6 +1,8 @@
 # Copyright (c) 2014-2015 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+
 #
 # Helpful routines for regression testing
 #
@@ -9,6 +11,8 @@
 import os
 import sys
 
+from binascii import hexlify, unhexlify
+from base64 import b64encode
 from decimal import Decimal, ROUND_DOWN
 import json
 import random
@@ -70,6 +74,15 @@ def check_json_precision():
 def count_bytes(hex_string):
     return len(bytearray.fromhex(hex_string))
 
+def bytes_to_hex_str(byte_str):
+    return hexlify(byte_str).decode('ascii')
+
+def hex_str_to_bytes(hex_str):
+    return unhexlify(hex_str.encode('ascii'))
+
+def str_to_b64str(string):
+    return b64encode(string.encode('utf-8')).decode('ascii')
+
 def sync_blocks(rpc_connections, wait=1):
     """
     Wait until everybody has the same block count
@@ -425,7 +438,7 @@ def assert_is_hash_string(string, length=64):
             "String %r contains invalid characters for a hash." % string)
 
 def satoshi_round(amount):
-    return  Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)
+    return Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)
 
 # Helper to create at least "count" utxos
 # Pass in a fee that is sufficient for relay and mining new transactions.