Support Profile module category

The implementation of hook_user (nodeaccess_password_user) does not make use of the $category parameter, which means that the passwords field appears on every tab on the profile form.

I believe this is a bug as profile forms belong to category that determines which tab they appear on, thus the behaviour here is inconsistent.

I do realise that the passwords field is not a real profile field and thus does not have a category, but this could easily be worked around by having an additional setting on the settings page called something like "password field profile category" stored in variable: nodeaccess_password_profile_category

the nodeaccess_password_user function could then be modified like:

Old version:
function nodeaccess_password_user($op, &$edit, &$account, $category = NULL) {
if ($op == "form" || $op == "register") {
$form = array();
...
New version:

function nodeaccess_password_user($op, &$edit, &$account, $category = NULL) {
$password_field_category = variable_get('nodeaccess_password_profile_category', 'account');
if (($op == "form" && $category == $password_field_category) || $op == "register") {
$form = array();
...

This is the first time I have raised an issue so I hope I have done it correctly.