LU-8998 utils: enlarge default inode size

LU-8998 utils: enlarge default inode size

Composite layout consumes more EA space, to hold a typical 3
components composite layout in inode, the default inode size
on MDT needs be bumped from 512 bytes to 1024 bytes. The default
OST inode size is changed from 256 bytes to 512 bytes as well,
because there will be more composite layout information stored
in OST object EA.

Performance tests shows that increased default inode size doesn't
impact performance, following are few numbers from the mdtest
result:

                  create  stat  removal  tree-create tree-remove
512/256 (origin): 16543  47292  32826    48          22
1024/512 (new)  : 16903  47404  32114    55          20

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: Ic5c08fd514f1111343f11129b1503a5ba2265ec7
Reviewed-on: https://review.whamcloud.com/24873
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>