Ignore RateLimitedOutputStreamSuite for now.

This test has been flaky. We can re-enable it after @tdas has a chance to look at it.

Author: Reynold Xin <rxin@apache.org>

Closes #54 from rxin/ratelimit and squashes the following commits:

1a12198 [Reynold Xin] Ignore RateLimitedOutputStreamSuite for now.
SPARK-1084.2 (resubmitted)

(Ported from https://github.com/apache/incubator-spark/pull/650 )

This adds one more change though, to fix the scala version warning introduced by json4s recently.

Author: Sean Owen <sowen@cloudera.com>

Closes #32 from srowen/SPARK-1084.2 and squashes the following commits:

9240abd [Sean Owen] Avoid scala version conflict in scalap induced by json4s dependency
1561cec [Sean Owen] Remove "exclude *" dependencies that are causing Maven warnings, and that are apparently unneeded anyway
SPARK-1121: Include avro for yarn-alpha builds

This lets us explicitly include Avro based on a profile for 0.23.X
builds. It makes me sad how convoluted it is to express this logic
in Maven. @tgraves and @sryza curious if this works for you.

I'm also considering just reverting to how it was before. The only
real problem was that Spark advertised a dependency on Avro
even though it only really depends transitively on Avro through
other deps.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #49 from pwendell/avro-build-fix and squashes the following commits:

8d6ee92 [Patrick Wendell] SPARK-1121: Add avro to yarn-alpha profile
Add Jekyll tag to isolate "production-only" doc components.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #56 from pwendell/jekyll-prod and squashes the following commits:

1bdc3a8 [Patrick Wendell] Add Jekyll tag to isolate "production-only" doc components.