oauthclient: cern documentation fix
oauthclient: cern documentation fix

* Fixes wrong code example in setup documentation for the CERN
  oauthclient.

Signed-off-by: Marco Neumann <3829486b93ec44395f0b980424bae9b6fb07b7bc@crepererum.net>

inveniosoftware/invenio,tiborsimko/invenio,inveniosoftware/invenio,tiborsimko/invenio