fix crash in Get Books when regenerating UIC files

Current versions of PyQt seem to generate code incompatible with our
class definition:

```
Traceback (most recent call last):
  File "/home/eschwartz/git/calibre/src/calibre/gui2/actions/store.py", line 49, in do_search
    return self.search()
           ^^^^^^^^^^^^^
  File "/home/eschwartz/git/calibre/src/calibre/gui2/actions/store.py", line 55, in search
    sd = SearchDialog(self.gui, self.gui, query)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/eschwartz/git/calibre/src/calibre/gui2/store/search/search.py", line 38, in __init__
    self.setupUi(self)
  File "/home/eschwartz/git/calibre/src/calibre/gui2/store/search/search_ui.py", line 84, in setupUi
    self.results_view = ResultsView(parent=self.verticalLayoutWidget)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: ResultsView.__init__() got an unexpected keyword argument 'parent'
```

The issue is that arguments forwarded to the PyQt class are now being
generated using keyword arguments rather than non-keyword args. As a
direct wrapper over a class belonging to another project, we really
should forward both types just in case.

src/calibre/gui2/store/search/results_view.py

@@ -39,8 +39,8 @@ class ResultsView(QTreeView):
     download_requested = pyqtSignal(object)
     open_requested = pyqtSignal(object)
 
-    def __init__(self, *args):
-        QTreeView.__init__(self,*args)
+    def __init__(self, *args, **kwargs):
+        QTreeView.__init__(self,*args, **kwargs)
 
         self._model = Matches()
         self.setModel(self._model)