pt-table-checksum reports wrong number of DIFFS

Due to this code:

            # Check each slave for checksum diffs.
            foreach my $slave ( @$slaves ) {
               eval {
                  my $diffs = $rc->find_replication_differences(
                     dbh => $slave->dbh(),
                     repl_table => $repl_table,
                     where => "db='$tbl->{db}' AND tbl='$tbl->{tbl}'",
                  );
                  PTDEBUG && _d(scalar @$diffs, 'checksum diffs on',
                     $slave->name());
                  if ( @$diffs ) {
                     $tbl->{checksum_results}->{diffs} = scalar @$diffs;
                  }
               };

Only the last slave's number of diffs is reported for the table. So with master --> slave1 --> slave2, if slave1 has 2 diffs (in 2 different chunks) but slave2 only has 1, the tool will report 1 for DIFFS for the table. Solution: report the max(diffs) for all slaves for each table, i.e. 2 in this case.

As a reminder, from the tool's docs:

"""
=item DIFFS

The number of chunks that differ from the master on one or more replicas.
"""

So 2 is the correct number to report because, all in all, 2 chunks do differ, not just 1.