Logged out warnings: fix phpdoc, props ocean90, see #23295

git-svn-id: http://core.svn.wordpress.org/trunk@23922 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Avoid an undefined index notice in wp_read_video_metadata(). props ocean90. fixes #23953.

git-svn-id: http://core.svn.wordpress.org/trunk@23923 1a063a9b-81f0-0310-95a4-ce76da25c4cd