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

* In `current_time()`, `break` is unreachable after `return`.
* In `add_query_arg()`, `$ret` is set twice before being used.
* In `wp_mkdir_p()`, `$dir_perms` is set twice before being used.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28325 602fd350-edb4-49c9-b593-d223f7449a82
In `paginate_links()`, `break` is unreachable after `return`.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28326 602fd350-edb4-49c9-b593-d223f7449a82
In `edit_post_link()`, `$post_type_obj` is unused.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28327 602fd350-edb4-49c9-b593-d223f7449a82
In `update_metadata_by_mid()`, `$original_value` is unused.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28328 602fd350-edb4-49c9-b593-d223f7449a82