some import clean-up in qt

electrum/gui/qt/qrcodewidget.py

@@ -1,3 +1,5 @@
+import os
+import qrcode
 
 from PyQt5.QtCore import *
 from PyQt5.QtGui import *
@@ -5,9 +7,6 @@ import PyQt5.QtGui as QtGui
 from PyQt5.QtWidgets import (
     QApplication, QVBoxLayout, QTextEdit, QHBoxLayout, QPushButton, QWidget)
 
-import os
-import qrcode
-
 import electrum
 from electrum.i18n import _
 from .util import WindowModalDialog