Remove a dead variable, `$start`, from `wp_dashboard_recent_comments()`.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28091 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove unused variable setting for `$revisions` in `wp_prepare_revisions_for_js()`.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28092 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove duplicate variable setting for `$link` in `wp_list_authors()`.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28093 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Avoid hiding 'Remove' buttons unrelated to custom headers.

props rzen, ehg.
fixes #27848.

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git-svn-id: http://core.svn.wordpress.org/trunk@28094 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Dead code in `wp-admin/includes/file.php`:
* In `wp_handle_upload()` and `wp_handle_sideload()`, `$ext` gets conditionally reset... and then is never used.
* In `request_filesystem_credentials()`, `$password` is initialized as an empty string. The variable is never used.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28096 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Only tie header button action events to the header controls.

props danielbachhuber.
fixes #28046. see #27848.

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git-svn-id: http://core.svn.wordpress.org/trunk@28097 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `edit_form_image_editor()`, `$filename` and `$title` are set and then unused. They shall be removed.

See #27882.


Built from https://develop.svn.wordpress.org/trunk@28271


git-svn-id: http://core.svn.wordpress.org/trunk@28099 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `general-template.php` - remove dead code:

* In `get_calendar()`, `$cache` is set twice. The first is useless. 
* In `wp_default_editor()`, `$user` is (accidentally) assigned in a condition. Since it is never used, this is unnecessary.
* In `language_attributes()`, `$output` is set twice before it is ever used. The first is unnecessary. 
* In `paginate_links()`, `$n` is set twice before it is ever used. The first is unnecessary.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28102 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Custom header: Avoid warnings in the process_default_headers() method.

props obenland.
fixes #27850.

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git-svn-id: http://core.svn.wordpress.org/trunk@28103 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Multisite: Fix case sensitivity regressions in 3.9.

props jeremyfelt.
fixes #27866.

Built from https://develop.svn.wordpress.org/trunk@28276


git-svn-id: http://core.svn.wordpress.org/trunk@28104 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `WP_List_Table::display_rows_or_placeholder()`, the call to `get_column_info()` in unnecessary and unused. The call to `get_column_count()` immediately after makes the same call internally.

See #27882.


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git-svn-id: http://core.svn.wordpress.org/trunk@28107 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Multisite: Treat 'www' as a special subdomain, reversing 3.9 regression.

props jeremyfelt.
fixes #27927.

Built from https://develop.svn.wordpress.org/trunk@28280


git-svn-id: http://core.svn.wordpress.org/trunk@28108 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Where a filter no longer exists, it need not be notated.

Fixes #24444. See r28258.

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git-svn-id: http://core.svn.wordpress.org/trunk@28111 1a063a9b-81f0-0310-95a4-ce76da25c4cd