primitivus: disconnected contact crash fix

fix IndexError when selecting a contact and hiding disconnected ones
fix bug 47

frontends/src/primitivus/contact_list.py

@@ -50,7 +50,10 @@ class ContactList(urwid.WidgetWrap, QuickContactList):
         widget, position = self.frame.body.get_focus()
         self.frame.body = self.__buildList()
         if position:
-            self.frame.body.set_focus(position)
+            try:
+                self.frame.body.set_focus(position)
+            except IndexError:
+                pass
         self.host.redraw()
 
     def update_jid(self, jid):