hw_wallet: do not mix qt and non-qt imports

plugins/hw_wallet/__init__.py

@@ -1,3 +1,2 @@
 from hw_wallet import BIP44_HW_Wallet
-from qt import QtHandlerBase
 from plugin import HW_PluginBase

plugins/ledger/qt.py

@@ -7,7 +7,7 @@ import PyQt4.QtCore as QtCore
 from electrum.i18n import _
 from electrum.plugins import hook
 from .ledger import LedgerPlugin, BTChipWallet
-from ..hw_wallet import QtHandlerBase
+from ..hw_wallet.qt import QtHandlerBase
 
 class Plugin(LedgerPlugin):
 

plugins/trezor/qt_generic.py

@@ -7,7 +7,7 @@ from PyQt4.Qt import QVBoxLayout, QLabel, SIGNAL
 from electrum_gui.qt.main_window import StatusBarButton
 from electrum_gui.qt.util import *
 from .plugin import TIM_NEW, TIM_RECOVER, TIM_MNEMONIC
-from ..hw_wallet import QtHandlerBase
+from ..hw_wallet.qt import QtHandlerBase
 
 from electrum.i18n import _
 from electrum.plugins import hook, DeviceMgr