Allow to edit a document locked by oneself

When a user manually locks a document and then tries to open it with DirectEdit, nothing happens.
The Drive logs indicates that the file will not be downloaded and edited because it is locked.

2016-10-14 10:47:03,499 3772 3604 DEBUG    nxdrive.direct_edit Doc Instructions.docx was locked by Administrator on 2016-10-14 10:32:24.691000+02:00, won't download it for edit

When the current user is the locker, we shoud allow the edition.