[SPARK-17803][TESTS] Upgrade docker-client dependency

[SPARK-17803: Docker integration tests don't run with "Docker for Mac"](https://issues.apache.org/jira/browse/SPARK-17803)

## What changes were proposed in this pull request?

This PR upgrades the [docker-client](https://mvnrepository.com/artifact/com.spotify/docker-client) dependency from [3.6.6](https://mvnrepository.com/artifact/com.spotify/docker-client/3.6.6) to [5.0.2](https://mvnrepository.com/artifact/com.spotify/docker-client/5.0.2) to enable _Docker for Mac_ users to run the `docker-integration-tests` out of the box.

The very latest docker-client version is [6.0.0](https://mvnrepository.com/artifact/com.spotify/docker-client/6.0.0) but that has one additional dependency and no usage yet.

## How was this patch tested?

The code change was tested on Mac OS X Yosemite with both _Docker Toolbox_ as well as _Docker for Mac_ and on Linux Ubuntu 14.04.

```
$ build/mvn -Pyarn -Phadoop-2.6 -Dhadoop.version=2.6.0 -Phive -Phive-thriftserver -DskipTests clean package

$ build/mvn -Pdocker-integration-tests -Pscala-2.11 -pl :spark-docker-integration-tests_2.11 clean compile test
```

Author: Christian Kadner <[email protected]>

Closes apache#15378 from ckadner/SPARK-17803_Docker_for_Mac.

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/DockerJDBCIntegrationSuite.scala

@@ -24,6 +24,7 @@ import scala.collection.JavaConverters._
 import scala.util.control.NonFatal
 
 import com.spotify.docker.client._
+import com.spotify.docker.client.exceptions.ImageNotFoundException
 import com.spotify.docker.client.messages.{ContainerConfig, HostConfig, PortBinding}
 import org.scalatest.BeforeAndAfterAll
 import org.scalatest.concurrent.Eventually

pom.xml

@@ -744,7 +744,7 @@
       <dependency>
         <groupId>com.spotify</groupId>
         <artifactId>docker-client</artifactId>
-        <version>3.6.6</version>
+        <version>5.0.2</version>
         <scope>test</scope>
         <exclusions>
           <exclusion>