Fix InvalidConfigurationException message after TagCapable support in logout_handler

[andrerom]

Finishes #486
Fixes FriendsOfSymfony/FOSHttpCache#456

[dbu]

thanks, specific examples help 👍

[dbu]

can you please adjust the test that assumes "ban" in the exception message as well?

[andrerom]

@dbu Done, remaining failure is irrelevant (tried downgrading to trusty, but same error there):

0.36s$ if [[ "$DOCCHECK" = true ]]; then make -C Resources/doc SPHINXOPTS='-nW' html; fi
make: Entering directory `/home/travis/build/FriendsOfSymfony/FOSHttpCacheBundle/Resources/doc'
sphinx-build -b html -d _build/doctrees  -nW . _build/html
Making output directory...
Running Sphinx v1.2.2
Exception occurred:
  File "/usr/lib/python2.7/dist-packages/sphinx/locale/__init__.py", line 191, in _
    return translators['sphinx'].ugettext(message)
KeyError: 'sphinx'
The full traceback has been saved in /tmp/sphinx-err-rX7zww.log, if you want to report the issue to the developers.

[dbu]

thanks!
re the sphinx failure: i tried to fix it in FOSHttpCache a while ago but did not find a solution: FriendsOfSymfony/FOSHttpCache#450