In `wp-includes/bookmark.php`, remove dead code:

* In `get_bookmarks()`, `$cache` is set twice before it is used. 
* In `sanitize_bookmark_field()`, `break` is unreachable after `return`

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28316 602fd350-edb4-49c9-b593-d223f7449a82
In `WP_Http_Curl::request()`, `$theResponse` is unused. There are other `curl_exec()` calls that do not return as well.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28317 602fd350-edb4-49c9-b593-d223f7449a82
In `wp-includes/class-wp-admin-bar.php`, `break` is unreachabled after `return`.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28318 602fd350-edb4-49c9-b593-d223f7449a82