Fix user.email, now contains the whole mail

Django's user.email currently contains only the first character of the email address. (Instead of tim.fechner@[...] it contains t)

After some investigation i've found the source of the bug.

In line 95 of ssoauth.views.ACSAuthNView.log_in_user() the get_attr function already resolves the first element of a value list. So it is obsolete to get the first element of the alleged list in line 86 of compat.update_user_data(), which is acutally a string, containing already the first email adress of the user.

Testet it already, but i donÄt know if it breaks some other things ...

So please review and merge this if possible.