login: Make register views more robust if some POST parameters are missing.

We fail to delete passsword/password confirm parameters if they are not
part of the POST parameters. But failing to delete them if they are not
present seems wrong. Better silently ignore if they are not present.

rhodecode/login/views.py

@@ -172,7 +172,7 b' class LoginView(object):'
         except formencode.Invalid as errors:
             defaults = errors.value
             # remove password from filling in form again
-            del defaults['password']
+            defaults.pop('password', None)
             render_ctx = self._get_template_context()
             render_ctx.update({
                 'errors': errors.error_dict,
@@ -260,8 +260,8 b' class LoginView(object):'
             raise HTTPFound(redirect_ro)
 
         except formencode.Invalid as errors:
-            del errors.value['password']
-            del errors.value['password_confirmation']
+            errors.value.pop('password', None)
+            errors.value.pop('password_confirmation', None)
             return self.register(
                 defaults=errors.value, errors=errors.error_dict)