quota: Add support to version 0 quota format

quota: Add support to version 0 quota format

Version 0 quota format differs from version 1 by having only 32-bit
counters for inodes and block limits. For many installations this is not
limiting and thus the format is widely used. Also quota tools still
create quota files with this format by default. Add support for this
quota format to e2fsprogs so that we can seamlessly convert quota files
in this format into our internal quota files.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>