Add a unit test using a dataset with a field order different than in …

[sbarnoud]

…the Avro schema

What changes were proposed in this pull request?

Added unit test to expose Avro field order problem

How was this patch tested?

NA

[sbarnoud]

This test willingly fails to show that Avro serialization depends on field order in the dataset, which in my opinion is not the expexted bahavior.

I propose in https://github.com/hortonworks-spark/shc/pull/248 a patch for that problem

[sbarnoud]

May i have a feedback? Travis failed, but this is normal, the test is just intended for that, and a PR propose a fix.