LU-16235 hsm: get a valid cookie for RAoLU request

LU-16235 hsm: get a valid cookie for RAoLU request

Add a way to get a valid cookie when nobody initializes
cdt_last_cookie.

RAoLU policy is allowed to queue a remove request with the
coordinator stopped. In that cases cdt_last_cookie can not be yet
initialize and the remove request can be queued with a conflicting
cookie.

This patch adds cdt_update_last_cookie() that reverses process the hsm
llog and stops at the first non-cancel action to determine the last
cookie.

Add the regression test sanity-hsm 26e.

Test-Parameters: testlist=sanity-hsm
Test-Parameters: testlist=sanity-hsm
Test-Parameters: testlist=sanity-hsm
Test-Parameters: testlist=sanity-hsm env=ONLY=26e,ONLY_REPEAT=30
Signed-off-by: Etienne AUJAMES <eaujames@ddn.com>
Signed-off-by: Nikitas Angelinas <nikitas.angelinas@hpe.com>
Change-Id: I6468a24b95fcb8768e12f40edfcea3ce8407281f
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51850
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>