[SPARK-9222] [MLlib] Make class instantiation variables in DistributedLDAModel private[clustering]

[MechCoder]

This makes it easier to test all the class variables of the DistributedLDAmodel.

[MechCoder]

@jkbradley

[MechCoder]

jenkins, my friend retest this please

[SparkQA]

Test build #38027 has finished for PR 7573 at commit dc81b99.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #48 has finished for PR 7573 at commit dc81b99.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[jkbradley]

LGTM, except for the merge conflicts. Btw, there may be a lot going on with LDA this coming week, so I'll try to focus on reviewing 1 LDA PR at a time to avoid unnecessary rebasing.

[MechCoder]

rebased and pushed by force

[SparkQA]

Test build #38313 has finished for PR 7573 at commit 2f1a293.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[jkbradley]

LGTM, merging with master. Thanks!

[MechCoder]

I noticed that there are todo's in the LDAModel.scala file. Would you want me to fix them up, because it would be a good exercise?

[jkbradley]

If one of them seems major, that would be great. But if they are minor, I think we should wait until after the 1.5 cutoff (in 1 week), so that more major changes can get in. This PR is making some big changes to LDA, btw: [https://github.com//pull/7507]