EX-4306 lipe: allow any SoM to count as size

EX-4306 lipe: allow any SoM to count as size

In lipe/policy.c:get_size(), allow any SoM attribute to be used as the
size since that is what existing users (Insight) expect.

Test-Parameters: trivial testlist=sanity-lipe
Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: I7f7be38f100840a327d8dc6f506ad73f2233a7b4
Reviewed-on: https://review.whamcloud.com/45809
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/46129