BIP32_HD_Wallet: Fix address derivation

Unfortunately there was root_name and root_derivation confusion
in the past for classes derived from BIP_32_HD_Wallet.
Address derivation used root_name and so would begin with 'x/'
whereas it should have begun with root_derivation, and so started
with 'm/'.

This fixes that old wart and removes some fudges from the trezor
code that used to work around it.

plugins/ledger/ledger.py

@@ -63,6 +63,10 @@ class BTChipWallet(BIP44_Wallet):
         assert not self.has_seed()
         return self.force_watching_only
 
+    def address_id(self, address):
+        # Strip the leading "m/"
+        return BIP44_Wallet.address_id(self, address)[2:]
+
     def get_client(self, noPin=False):
         if not BTCHIP:
             self.give_error('please install github.com/btchip/btchip-python')

plugins/trezor/client.py

@@ -98,7 +98,7 @@ def trezor_client_class(protocol_mixin, base_client, proto):
             '''Convert bip32 path to list of uint32 integers with prime flags
             0/-1/1' -> [0, 0x80000001, 0x80000001]'''
             path = []
-            for x in n.split('/'):
+            for x in n.split('/')[1:]:
                 prime = 0
                 if x.endswith("'"):
                     x = x.replace('\'', '')

plugins/trezor/plugin.py

@@ -100,7 +100,6 @@ class TrezorCompatibleWallet(BIP44_Wallet):
 
         # When creating a wallet we need to ask the device for the
         # master public key
-        derivation = derivation.replace(self.root_name, self.prefix() + "/")
         xpub = self.get_public_key(derivation)
         return xpub, None