replaced last redirections to src/delete_message.php with sqimap commands.

replaced last redirections to src/delete_message.php with sqimap commands.
sqimap_msgs_list_delete() is used instead of sqimap_delete_messages(),
because sqimap_delete_messages() is marked as deprecated.

PS.
sqimap_msgs_list_delete($imap_stream, $mailbox, $id, $bypass_trash=false)
sqimap_msgs_list_copy  ($imap_stream, $id, $mailbox, $handle_errors = true)
sqimap_msgs_list_move  ($imap_stream, $id, $mailbox, $handle_errors = true)

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@9209 7612ce4b-ef26-0410-bec9-ea0150e637f0