First pass at fixing notices

[bananastalktome]

In setting up wp-super-cache for the first time, I found myself seeing many php debug notices on my development instance. I patched several, noticed a few I was not sure how to patch (see below), and since this was just an initial pass at this I am sure there are other use cases I did not come across that still generate notices.

This patch fixes many of the debug notices, however given my relative unfamiliarity with the code there were three I was unsure of:

In the plugin admin settings area on the 'Contents' tab:

• when 'List all cached files' clicked:
  • Notice: Undefined variable: cached_list in <HTDOCS>/wp-content/plugins/wp-super-cache/wp-cache.php on line 2319
  • Notice: Undefined variable: expired_list in <HTDOCS>/wp-content/plugins/wp-super-cache/wp-cache.php on line 2335

• when 'delete cache on all blogs' clicked:
  • Notice: Undefined variable: wp_cache_fsize in <HTDOCS>/wp-content/plugins/wp-super-cache/wp-cache.php on line 2245