fs/quota: remove unused macro

__QUOTA_V2_PARANOIA  macro is never used. better to remove it.

Link: https://lore.kernel.org/r/1579602334-57039-1-git-send-email-alex.shi@linux.alibaba.com


Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Jan Kara <jack@suse.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>