LU-14191 lod: comp stripe count limit check

LU-14191 lod: comp stripe count limit check

when creating a PFL file of 2K stripes, they are shrinked to 700+,
because lod_get_stripe_count() checks the space left after taking
given 2K stripes into account, and the total amount of stripes that
fits into EA is 2700+.

when creating a SEL file of 2K stipes, it fails because the extension
component is also taking into account despite the fact it is never
initialised and due to the above logic 2x2k stripes leaves no space
in EA.

HPE-bug-id: LUS-9589
Signed-off-by: Vitaly Fertman <c17818@cray.com>
Change-Id: Ibeb063472d477e393646860010823fed5acb8382
Reviewed-by: Alexander Boyko <c17825@cray.com>
Reviewed-by: Artem Blagodarenko <c17828@cray.com>
Tested-by: Elena Gryaznova <c17455@cray.com>
Reviewed-on: https://review.whamcloud.com/40895
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Artem Blagodarenko <artem.blagodarenko@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>