pep8 blank lines fixes

flake8 --select W391,E302,E301,E304

autopep8 can't fix W391 even though it claims it can.
Fixed using a simple custom script.

modules/caissedepargne/pages.py

@@ -39,6 +39,7 @@ class _LogoutPage(Page):
         except BrokenPageError:
             pass
 
+
 class LoginPage(_LogoutPage):
     def login(self, login):
         self.browser.select_form(name='Main')
@@ -83,6 +84,7 @@ class LoginPage(_LogoutPage):
 class ErrorPage(_LogoutPage):
     pass
 
+
 class UnavailablePage(Page):
     def on_loaded(self):
         try: