[SPARK-6894]spark.executor.extraLibraryOptions => spark.executor.extraLibraryPath

https://issues.apache.org/jira/browse/SPARK-6894

cc vanzin

Author: WangTaoTheTonic <wangtao111@huawei.com>

Closes #5506 from WangTaoTheTonic/SPARK-6894 and squashes the following commits:

4b7ced7 [WangTaoTheTonic] spark.executor.extraLibraryOptions => spark.executor.extraLibraryPath

launcher/src/main/java/org/apache/spark/launcher/SparkLauncher.java

@@ -52,7 +52,7 @@ public class SparkLauncher {
   /** Configuration key for the executor VM options. */
   public static final String EXECUTOR_EXTRA_JAVA_OPTIONS = "spark.executor.extraJavaOptions";
   /** Configuration key for the executor native library path. */
-  public static final String EXECUTOR_EXTRA_LIBRARY_PATH = "spark.executor.extraLibraryOptions";
+  public static final String EXECUTOR_EXTRA_LIBRARY_PATH = "spark.executor.extraLibraryPath";
   /** Configuration key for the number of executor CPU cores. */
   public static final String EXECUTOR_CORES = "spark.executor.cores";