ms-delete-site.php using incorrect vars

[sivel]

When using a subdirectory install ms-delete-site.php displays something similar to the following when trying to delete ​http://example.org/somesite/:

I'm sure I want to permanently disable my site, and I am aware I can never get it back or use example.org/ again.

I imagine this message should actually reflect example.org/somesite/ instead of just example.org/

When not a sub domain install we are using $current_site instead of $current_blog, likely we could be using $current_blog here

Looks sensible to me that it would always use $current_blog there.

(In [15245]) use site details on confirm delete site, props sivel, fixes #13873.diff