Incorrect hook_user 'view' implementation

Hi,

this is only a very small issue, but during module development I stumbled over it, because I made the same 'mistake'. :-)
I wanted to add content to the history section of the user profile and since I did not name my outer array too the "Masquerade" link was overwritten by my module.

The hook_user doc says:

"view": An associative array of associative arrays. The outer array should be keyed by category name.

I've included the patch to resolve this issue.