LU-11881 utils: silence error message

LU-11881 utils: silence error message

llapi_get_poollist prints an error message
in case of reallocating the buffer
and successful completion.

Cray-bug-id: LUS-6185
Test-Parameters: testlist=ost-pools
Change-Id: I0ca1f25edf3f4c89525d41f2deab8d25ec9e0516
Signed-off-by: Alexander Zarochentsev <c17826@cray.com>
Reviewed-on: https://review.whamcloud.com/34086
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>