LU-13314 test: add 56ob to ALWAYS_EXCEPT for now

LU-13314 test: add 56ob to ALWAYS_EXCEPT for now

There is a problem that 'lfs find' try to calculate
365 days for one year, this will be problem for leap year.

We need fix test or codes, before that let's disable this test
to make other patches landed possibly.

Change-Id: I79d34ce29657b4d149a0fbe82220cfefa0c60378
Test-Parameters: trivial testlist=sanity envdefinitions=ONLY=56ob
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/37767
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>