EX-4041 tests: look for lamigo log on MDS

EX-4041 tests: look for lamigo log on MDS

hot-pools tests 7, 8 and 10 grep the lamigo log from a
client node looking for job completion or other lamigo
information.  The lamigo log is written to a space on the
MDS.  Change the tests to cat the log file on the MDS
and pipe that to grep.

Test-Parameters: trivial testlist=hot-pools

Change-Id: I78813d6188216b2529e1f6e41252bc6fe1fc9514
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/45218
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>