EX-4103 lamigo: do not mark cold pool mirror "prefer"

EX-4103 lamigo: do not mark cold pool mirror "prefer"

When lamigo_check_hot_on_cold() calls lamigo_new_job_for_hot() it
passes "tgt_pools" as the "tgt" pool argument, for the case when an
active file in the hot pool needs to be mirrored to the cold pool,
unlike other callers pass "src_pools" as "tgt" to mirror to the hot
pool.  This should not result in the cold pool mirror being marked
"prefer", which can trigger a chain of later problems with the file.

Fix comment in lamigo_check_hot_on_cold() to make it clear what case
is being checked, since it described the opposite of what is done.

Test-Parameters: trivial testlist=hot-pools
Fixes: e582abc629e ("EX-978 lamigo: set prefer flag on fast replica")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Iad48d6eb2d57817241b8ca3c22c03e38b93ebbe5
Reviewed-on: https://review.whamcloud.com/45345
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/45351
Tested-by: jenkins <devops@whamcloud.com>