Provide an offline tool to disable quota. For kernel which skip_balance doesn't work, there is no way to disable quota on huge fs with balance, as quota will cause balance to hang for a long long time for each tree block switch. So add an offline rescue tool to disable quota. Reported-by: Dan Merillat <dan.merillat@gmail.com> Signed-off-by: Qu Wenruo <wqu@suse.com>