LU-14049 utils: manage thread resources in alr_batch_print()

LU-14049 utils: manage thread resources in alr_batch_print()

In alr_batch_print(), create the sort and print thread with the
detached attribute. Protect against concurrent write the the batch
output file. Ensure that memory is freed in error cases.

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: Ibf1b299bd15f5d189a2302ce476bf2ef986a85b1
Reviewed-on: https://review.whamcloud.com/40309
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>