(occur-mode-map): Bind "q" to `delete-window'.

(occur-mode-map): Bind "q" to `delete-window'.
(occur-1): If one of the buffers we're searching is the *Occur* buffer
itself, handle it by creating a temporary buffer.  If any of the
buffers being searched are killed, note that in the search result
message.  Also, set local variables before we possibly kill the
buffer.