LU-10994 echo: remove client operations from echo objects

LU-10994 echo: remove client operations from echo objects

Remove the client (io, page, lock) operations from echo_client
objects. This will facilitate the simplification of CLIO.

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: If9e55c7d54c171aa2e1bcf272641c2bd6be8ad48
Reviewed-on: https://review.whamcloud.com/47240
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>