Author: Dongsheng Cai
MDL-27330 repository dropbox plugin Dropbox changed authorization URL, and added a few error check code
http://git.moodle.org/gw?p=moodle.git;a=commit;h=810aea11df5a9b3714f499de6cc7397373705e33
http://github.com/moodle/moodle/commit/810aea11df5a9b3714f499de6cc7397373705e33
+ 2.1dev en [repositoryerror,core_repository]