Searching for user produces notice/warning

Problem/Motivation

When searching for user on the Grants tab for nodes with version 1.6, we get a notice and a warning :

Notice: Undefined index: uid in nodeaccess_grants_form() (line 235 of /srv/www/dev-fondation/sites/all/modules/nodeaccess/nodeaccess.module).
Warning: array_keys() expects parameter 1 to be array, null given in nodeaccess_grants_form() (line 235 of /srv/www/dev-fondation/sites/all/modules/nodeaccess/nodeaccess.module).

That line 235 was simply out of place, it needs to be inside the isset check just below :

    if (isset($form_values['uid']) && count($form_values['uid'])) {
      $uid = array_keys($form_values['uid']);
      $query->condition('uid', $uid, 'NOT IN');
    }

Steps to reproduce:
- Go to the "Grants" tab on any node (i.e. /node/1234/grant ).
- Start typing a username where it says "Enter names to search for users".
- Click a username from the autocomplete suggestions.
- Click "Search"
- Check "recent log messages" / "watchdog-show"
- You'll see the aforementioned "Notice" and "Warning" log messages.

Proposed resolution

(Description of the proposed solution, the rationale behind it, and workarounds for people who cannot use the patch.)

Remaining tasks

Patch coming up...

User interface changes

API changes

Data model changes