Remove unnecessary $posts_per_page global in admin.php

[nacin]

First discussed in #11385.

There is an orphaned $posts_per_page = get_option('posts_per_page') in the admin.php bootstrap. The variable is never used and appears to be an artifact that is left over from before the time of screen options.

The posts_per_page option is the reading option for the number of posts to display per page in a theme.

In the off-chance a plugin used this variable, it is overwritten in post.php anyway, and would provide incorrect values on any other page, as they have their own *_per_page user options. As of [12375] they also have a complete set of filters as well.

If someone feels that broken back compat is necessary here, then we can wontfix.

[hakre]

I took a look as well and did not find any use of the global $posts_per_page within the admin. Looks OK to me to be zapped.

[hakre]

reviewed and tested again: OK. patch applies clean.

[nacin]

[12551], thanks westi.