LU-13904 tests: don't assume echo_client is a module.

LU-13904 tests: don't assume echo_client is a module.

The upstream lustre client can be compiled with all code
in the kernel - no modules.
So testing if the module is loaded gets incorrect results.
So add a test to see if the functionalty is already present,
and don't load a module if none is needed.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Id630107d57f473dfdc21687a4964e1ca4c83efe4
Reviewed-on: https://review.whamcloud.com/39655
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>