LU-12758 quota: clear default flag for new ID

LU-12758 quota: clear default flag for new ID

When setting the quota limits as 0 by "lfs setquota", the default
flag won't be cleared if the lquota_entry is just created for some
quota ID at the first time because the quota limits are the same.

Change-Id: I7f44ce0cb13783ca5bede2f55cd0707f1ccbc8ca
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/36236
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shilong Wang <wshilong@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>