Remove redundant assignment. see [28379], [28534].

see #22400.

git-svn-id: https://develop.svn.wordpress.org/trunk@28538 602fd350-edb4-49c9-b593-d223f7449a82
These functions import `$wpdb` but do not use it.

See #27882.


git-svn-id: https://develop.svn.wordpress.org/trunk@28539 602fd350-edb4-49c9-b593-d223f7449a82
Use correct variable. see [28534], [28538].

see #22400.

git-svn-id: https://develop.svn.wordpress.org/trunk@28540 602fd350-edb4-49c9-b593-d223f7449a82