## What changes were proposed in this pull request?

We are currently detecting the changes in `R/` directory only and then trigger AppVeyor tests.

It seems we need to tests when there are Scala codes dedicated for R in `core/src/main/scala/org/apache/spark/api/r/`, `sql/core/src/main/scala/org/apache/spark/sql/api/r/` and `mllib/src/main/scala/org/apache/spark/ml/r/` too.

This will enables the tests, for example, for SPARK-20088.

## How was this patch tested?

Tests with manually created PRs.

- Changes in `sql/core/src/main/scala/org/apache/spark/sql/api/r/SQLUtils.scala` https://github.com/spark-test/spark/pull/13
- Changes in `core/src/main/scala/org/apache/spark/api/r/SerDe.scala` https://github.com/spark-test/spark/pull/12
- Changes in `README.md` https://github.com/spark-test/spark/pull/14

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #17427 from HyukjinKwon/SPARK-20092.

[SPARK-19660][CORE][SQL] Replace the configuration property names that are deprecated in the version of Hadoop 2.6

## What changes were proposed in this pull request?

Replace all the Hadoop deprecated configuration property names according to [DeprecatedProperties](https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-common/DeprecatedProperties.html).

except:
https://github.com/apache/spark/blob/v2.1.0/python/pyspark/sql/tests.py#L1533
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala#L987
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/main/scala/org/apache/spark/sql/execution/command/SetCommand.scala#L45
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala#L614

## How was this patch tested?

Existing tests

Author: Yuming Wang <wgyumg@gmail.com>

Closes #16990 from wangyum/HadoopDeprecatedProperties.

## What changes were proposed in this pull request?

- Remove support for Hadoop 2.5 and earlier
- Remove reflection and code constructs only needed to support multiple versions at once
- Update docs to reflect newer versions
- Remove older versions' builds and profiles.

## How was this patch tested?

Existing tests

Author: Sean Owen <sowen@cloudera.com>

Closes #16810 from srowen/SPARK-19464.

[SPARK-17200][PROJECT INFRA][BUILD][SPARKR] Automate building and testing on Windows (currently SparkR only)

## What changes were proposed in this pull request?

This PR adds the build automation on Windows with [AppVeyor](https://www.appveyor.com/) CI tool.

Currently, this only runs the tests for SparkR as we have been having some issues with testing Windows-specific PRs (e.g. https://github.com/apache/spark/pull/14743 and https://github.com/apache/spark/pull/13165) and hard time to verify this.

One concern is, this build is dependent on [steveloughran/winutils](https://github.com/steveloughran/winutils) for pre-built Hadoop bin package (who is a Hadoop PMC member).

## How was this patch tested?

Manually, https://ci.appveyor.com/project/HyukjinKwon/spark/build/88-SPARK-17200-build-profile
This takes roughly 40 mins.

Some tests are already being failed and this was found in https://github.com/apache/spark/pull/14743#issuecomment-241405287.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #14859 from HyukjinKwon/SPARK-17200-build.