Adding terms without AJAX strips "taxonomy" query arg

[szaqal21]

I've wrote a plugin which disables AJAX for managment of taxonomy terms and I think I've found a bug. If I add new term for taxonomy "category", browser is being redirected to edit-tags.php widthout "taxonomy=category" arg. After some search in core I've found that redirect location is being set wrong - I think. Line 84 in edit-tags.php

<?php
$location = add_query_arg( 'message', 1, $location );

uses $location as url, shouldn't it be $referer as other actions do? $location at this point equals to false.

[peterwilsoncc]

I could reproduce this.

At first glance, looks like regression following [38750], putting on the 4.7.1 milestone for follow up.

[peterwilsoncc]

Confirmed as a regression, 39328.diff​ uses fix suggested by szaqal21.

[peterwilsoncc]

In 39649:

Taxonomy: Redirect to current taxonomy when adding a term without AJAX.

Fixes a regression in which adding terms via a full page refresh, ie without AJAX, would always redirect to the tags taxonomy.

Props szaqal21.
Fixes #39328 for trunk.

[peterwilsoncc]

Reopening for back-porting to 4.7

[dd32]

In 39652:

Taxonomy: Redirect to current taxonomy when adding a term without AJAX.

Fixes a regression in which adding terms via a full page refresh, ie without AJAX, would always redirect to the tags taxonomy.

Props szaqal21, peterwilsoncc.
Merges [39649] to the 4.7 branch.
Fixes #39328 for 4.7.