LU-11670 tests: do not fail the first half in sanityn test 103

LU-11670 tests: do not fail the first half in sanityn test 103

There are two halves in sanityn test 103. The first half is to
reproduce the problem of incorrect size when using lockahead
and the second half is to verify that the fix works. Sometimes,
the problem cannot be reproduced in the first half test, so we
should not fail the whole test.

Test-Parameters: trivial fstype=zfs \
mdscount=2 mdtcount=4 testlist=sanityn,sanityn,sanityn

Test-Parameters: trivial fstype=ldiskfs \
mdscount=2 mdtcount=4 testlist=sanityn,sanityn,sanityn

Lustre-change: https://review.whamcloud.com/36303
Lustre-commit: a88d0aa76c62e3074a05e869c9f0ba7ac128300f

Change-Id: Ib6c82bfe512ac072104abfcb406e2ef1bd6a6a02
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Patrick Farrell <farr0186@gmail.com>
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/36407
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>