[SPARK-10086] [MLlib] [Streaming] [PySpark] ignore StreamingKMeans test in PySpark for now

[mengxr]

I saw several failures from recent PR builds, e.g., https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/50015/consoleFull. This PR marks the test as ignored and we will fix the flakyness in SPARK-10086.

@gliptak Do you know why the test failure didn't show up in the Jenkins "Test Result"?

cc: @jkbradley

[SparkQA]

Test build #50049 has finished for PR 10909 at commit d7e7aa9.

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

[gliptak]

@mengxr Does the test only fail under one of the Python versions?

[jkbradley]

@mengxr Were these all the same test failing? Before, I had seen similar failures from multiple tests.
Also, did the failure rate seem to increase recently?

[jkbradley]

LGTM though, if you want to go ahead and disable it

[mengxr]

Some (not all) failures in the last 4 days:

• https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/50016/testReport/
• https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/49996/testReport/
• https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/49989/testReport/
• https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/49870/testReport/

@gliptak The builds listed above have XML report, so I can track test failures. However, the one I posted in PR description (build 50015) doesn't report test result. The test failed with Python 3.4.

Merged into master.

[maver1ck]

@jkbradley
What about merging this to branch-1.6?
I have same problem here:
#14390