Server hangs/crashes on when an admin delete its own account

[ahmedkrmn]

When the currently logged in admin user deletes their account, the server hangs and the page is stuck on reload until it crashes.

Problem:

Fix: #83

Disallow currently logged in admin from deleting their own account and display an error message.

[llaske]

It's true but it's a borderline case: the admin remove himself.
Plus we're planning to create a Teacher profile avoid this sort of issue.

[ahmedkrmn]

@llaske Shall I close the PR then ?!
I think we can go with the bug fix #83 until we create the teacher profile.

[llaske]

No, I've merged your fix. Thanks.