OPML:
* Learn how OPML works, cry.
* Remove unused globals in `startElement()`
* Stop using variable variables in `startElement()`

Tested with the OPML importer plugin

See #27881.

Built from https://develop.svn.wordpress.org/trunk@28743


git-svn-id: http://core.svn.wordpress.org/trunk@28557 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Don't use variable variables in `setup-config.php` (Step 2).
See #27881.

Built from https://develop.svn.wordpress.org/trunk@28744


git-svn-id: http://core.svn.wordpress.org/trunk@28558 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Don't use variable variables in `user-new.php`. Test by causing errors when creating a new user.

See #27881.

Built from https://develop.svn.wordpress.org/trunk@28745


git-svn-id: http://core.svn.wordpress.org/trunk@28559 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Don't use variable variables in `wp_reset_vars()`. Test by searching in list tables, etc.

See #27881.

Built from https://develop.svn.wordpress.org/trunk@28746


git-svn-id: http://core.svn.wordpress.org/trunk@28560 1a063a9b-81f0-0310-95a4-ce76da25c4cd