Extend fsck diagnostic output to help tracking down duplicate data point cause

[IzakMarais]

After a discussion on the Google group, Manolama requested a log an issue here.

I wrote:

It would be great if the tools for identifying the source of duplicate data be improved. I also have this problem.

Since I know the query that causes the problem, I know the metric name. However I don't know the tags. Running fsck gives some output that might be useful?

2015-03-26 08:07:51,775 ERROR [main] Fsck: More than one column had a value for the same     timestamp: timestamp: (1427357192000)
[24, -125]
[24, -117]

To which Manolama replied

... yeah, if I'm not dumping the row key before or after that line, please open an issue and I'll get it in there. Sorry!

I can confirm: there is no row key before or after the line.

[manolama]

Ah yeah, this actually fixed in 2.1:

2015-04-19 13:35:58,238 INFO  [Fsck #0] Fsck: More than one column had a value for the same timestamp: (1356998400000 - Mon Dec 31 16:00:00 PST 2012)
    row key: (00000150E22700000001000001)
    write time: (1388534400000)  compacted: (false)  qualifier: [0, 0] <--- keep oldest
    write time: (1388534400001 - Tue Dec 31 16:00:00 PST 2013)  compacted: (false)  qualifier: [0, 11] value: 500.79998779296875