Add missing id attribute to "Search Installed Themes" input.

Merges [26885] to the 3.8 branch.

props SergeyBiryukov.
fixes #26599.


git-svn-id: https://develop.svn.wordpress.org/branches/3.8@26936 602fd350-edb4-49c9-b593-d223f7449a82
Pass the $user_id to the admin_color_scheme_picker hook for context.

Prevents the admin color scheme from changing when editing another user.

Merges [26924] to the 3.8 branch.
see #26607.


git-svn-id: https://develop.svn.wordpress.org/branches/3.8@26937 602fd350-edb4-49c9-b593-d223f7449a82