Rename rpcuser.py to rpcauth.py

This script creates `rpcauth` entries for bitcoin.conf,
not the deprecated `rpcuser` entry, so this changes the name
of the script to match.

share/rpcauth/rpcauth.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+# Copyright (c) 2015-2016 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying 
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+import hashlib
+import sys
+import os
+from random import SystemRandom
+import base64
+import hmac
+
+if len(sys.argv) < 2:
+    sys.stderr.write('Please include username as an argument.\n')
+    sys.exit(0)
+
+username = sys.argv[1]
+
+#This uses os.urandom() underneath
+cryptogen = SystemRandom()
+
+#Create 16 byte hex salt
+salt_sequence = [cryptogen.randrange(256) for i in range(16)]
+hexseq = list(map(hex, salt_sequence))
+salt = "".join([x[2:] for x in hexseq])
+
+#Create 32 byte b64 password
+password = base64.urlsafe_b64encode(os.urandom(32))
+
+digestmod = hashlib.sha256
+
+if sys.version_info.major >= 3:
+    password = password.decode('utf-8')
+    digestmod = 'SHA256'
+ 
+m = hmac.new(bytearray(salt, 'utf-8'), bytearray(password, 'utf-8'), digestmod)
+result = m.hexdigest()
+
+print("String to be appended to bitcoin.conf:")
+print("rpcauth="+username+":"+salt+"$"+result)
+print("Your password:\n"+password)