Author: David Monllao
MDL-58905 auth_oauth2: No linked accounts if the plugin is not enabled
http://git.moodle.org/gw?p=moodle.git;a=commit;h=011591a1483dab58c5f9ba92e45998ad7016fbeb
http://github.com/moodle/moodle/commit/011591a1483dab58c5f9ba92e45998ad7016fbeb
+ 3.3 en [notenabled,auth_oauth2]