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.

This patch is back-ported from the following one:
Lustre-commit: ce86e23b21ccffc395089578c0ca356de219ac88
Lustre-change: https://review.whamcloud.com/36236

Change-Id: I7f44ce0cb13783ca5bede2f55cd0707f1ccbc8ca
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/38808
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>