LU-14777 lod: fix E2BIG on create

LU-14777 lod: fix E2BIG on create

A fix solves 2 cases that caused create to fail
with -E2BIG.
1. Stripe count number should be calculated depending
on LOV_PATTERN_OVERSTRIPING flag.
2. In a case of failover lod_comp_entry_stripe_count
may return 0 if all OST targets have been disconnected.
Return EAGAIN in such case to calculate this later,
when at least one OST would be connected.

HPE-bug-id: LUS-9485
Fixes: aa72de32 ("LU-11691 lov: Limit layout size to max ea size")
Change-Id: I26cad4903d5dd6197fe1384013fbba8b2c76487c
Signed-off-by: Sergey Cheremencev <sergey.cheremencev@hpe.com>
Reviewed-on: https://review.whamcloud.com/44043
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>