[SPARK-9327] [docs] Fix documentation about classpath config options.

[vanzin]

No description provided.

[SparkQA]

Test build #38400 has finished for PR 7651 at commit 2923e23.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • abstract class InternalRow extends Serializable
  • class GenericRow(protected[sql] val values: Array[Any]) extends Row
  • class GenericInternalRow(protected[sql] val values: Array[Any]) extends InternalRow
  • class GenericInternalRowWithSchema(values: Array[Any], val schema: StructType)
  • class GenericMutableRow(val values: Array[Any]) extends MutableRow

[srowen]

LGTM

[andrewor14]

LGTM2, feel free to merge it

[vanzin]

Merged to master.