Ticket update

[yllen]

If the ticket is New and the requester is the user logged and there is no follow up or no task
a post only can update his ticket.

A ticket New like described top has no button to add an item in Elements tab of the created ticket

With no right to update a ticket, a user in standard interface can do it (bug with this commit b4b8d79)

[orthagh]

for reference: #835

[orthagh]

i push for master the above pr (#994) to avoid the following conflict (issues : #596 & #835):

• with your version, self-service user can add items
• with my version, closed tickets still display items

I can't found the first issue in 0.90 branch, could you check again ? i did the inverse in fact, i'll redo it soon