LU-16951 test: don't call echo in function call

LU-16951 test: don't call echo in function call

In sanity-quota, the call '$(get_slave_nr expr "foo")' will fail
if there is "echo" call in "wait_update_facet/wait_update_cond".

Test-Parameters: trivial
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Change-Id: Ib35bf8ccd7eb121a0a2852ba7ed69ad9b01f271a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51615
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Deiter <alex.deiter@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>