Fix a regression in wp_mkdir_p() where the $mode of the parent folder is not correctly applied to all created paths.

Merges [26449] and [26927] from 3.8.x to the 3.7 branch.

props dd32.
fixes #25822.


git-svn-id: https://develop.svn.wordpress.org/branches/3.7@27887 602fd350-edb4-49c9-b593-d223f7449a82
Prefix the notoptions cache key in the multisite site-options group with $wpdb->siteid to avoid collisions.

Merges [26304] (and [26305]) from 3.8 to the 3.7 branch.

props wonderboymusic.
fixes #25883.


git-svn-id: https://develop.svn.wordpress.org/branches/3.7@27888 602fd350-edb4-49c9-b593-d223f7449a82