request account_id in wizard, for hardware wallets. cleanup bip44 code

plugins/trezor/clientbase.py

@@ -3,7 +3,7 @@ from struct import pack
 
 from electrum.i18n import _
 from electrum.util import PrintError, UserCancelled
-from electrum.keystore import BIP44_KeyStore
+from electrum.keystore import bip39_normalize_passphrase
 from electrum.bitcoin import EncodeBase58Check
 
 
@@ -65,7 +65,7 @@ class GuiMixin(object):
         passphrase = self.handler.get_passphrase(msg, self.creating_wallet)
         if passphrase is None:
             return self.proto.Cancel()
-        passphrase = BIP44_KeyStore.normalize_passphrase(passphrase)
+        passphrase = bip39_normalize_passphrase(passphrase)
         return self.proto.PassphraseAck(passphrase=passphrase)
 
     def callback_WordRequest(self, msg):

plugins/trezor/plugin.py

@@ -22,14 +22,13 @@ from ..hw_wallet import HW_PluginBase
 TIM_NEW, TIM_RECOVER, TIM_MNEMONIC, TIM_PRIVKEY = range(0, 4)
 
 class TrezorCompatibleKeyStore(Hardware_KeyStore):
-    root = "m/44'/0'"
-    account_id = 0
 
     def load(self, storage, name):
         self.xpub = storage.get('master_public_keys', {}).get(name)
+        self.account_id = storage.get('account_id')
 
     def get_derivation(self):
-        return self.root + "/%d'"%self.account_id
+        return "m/44'/0'/%d'"%self.account_id
 
     def get_client(self, force_pair=True):
         return self.plugin.get_client(self, force_pair)