Failure when Global Redirect de-slash enabled

I suspect that the issue may occur due to Global Redirect calling drupal_goto during hook_init, and the new token not being correctly sent to the browser.

I don't remember testing if the same failure occurred when accessing a non-alias path (with configuration to redirect to the aliased path)

Just tested a basic configuration, using de-slash on a basic node url. I think the process flow is as follows:

1. persistent_login_boot() checks if the user has a PL token, and if successful invalidates the old token and calls user_external_login().

2. hook_init is called, hitting global_redirect_init() first. Global redirect detects the ending slash, and calls drupal_goto() with the deslashed address. An updated token is seemingly not generated (and consequently not stored or sent to the user in a new cookie value).

3. the user loads the deslashed page, but (a) PL login has set the session to not check for a valid PL again in hook_boot() and (b) the user's cookie sent with the request matches the old (now invalid token)

I think getting #943280: Deleting expired persistent login cookie for Boost compatibility tested and committed may make this somewhat easier to resolve

Bumping version; fix in 7.x first and then backport to 6.x if possible.