Rename testExecutorEnvs --> executorEnvs.

This was changed, but in fact, it's used for things other than tests.
So I've changed it back.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #747 from pwendell/executor-env and squashes the following commits:

36a60a5 [Patrick Wendell] Rename testExecutorEnvs --> executorEnvs.

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -276,19 +276,18 @@ class SparkContext(config: SparkConf) extends Logging {
     .getOrElse(512)
 
   // Environment variables to pass to our executors.
-  // NOTE: This should only be used for test related settings.
-  private[spark] val testExecutorEnvs = HashMap[String, String]()
+  private[spark] val executorEnvs = HashMap[String, String]()
 
   // Convert java options to env vars as a work around
   // since we can't set env vars directly in sbt.
   for { (envKey, propKey) <- Seq(("SPARK_TESTING", "spark.testing"))
     value <- Option(System.getenv(envKey)).orElse(Option(System.getProperty(propKey)))} {
-    testExecutorEnvs(envKey) = value
+    executorEnvs(envKey) = value
   }
   // The Mesos scheduler backend relies on this environment variable to set executor memory.
   // TODO: Set this only in the Mesos scheduler.
-  testExecutorEnvs("SPARK_EXECUTOR_MEMORY") = executorMemory + "m"
-  testExecutorEnvs ++= conf.getExecutorEnv
+  executorEnvs("SPARK_EXECUTOR_MEMORY") = executorMemory + "m"
+  executorEnvs ++= conf.getExecutorEnv
 
   // Set SPARK_USER for user who is running SparkContext.
   val sparkUser = Option {
@@ -296,7 +295,7 @@ class SparkContext(config: SparkConf) extends Logging {
   }.getOrElse {
     SparkContext.SPARK_UNKNOWN_USER
   }
-  testExecutorEnvs("SPARK_USER") = sparkUser
+  executorEnvs("SPARK_USER") = sparkUser
 
   // Create and start the scheduler
   private[spark] var taskScheduler = SparkContext.createTaskScheduler(this, master)

core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala

@@ -54,7 +54,7 @@ private[spark] class SparkDeploySchedulerBackend(
     }
 
     val command = Command(
-      "org.apache.spark.executor.CoarseGrainedExecutorBackend", args, sc.testExecutorEnvs,
+      "org.apache.spark.executor.CoarseGrainedExecutorBackend", args, sc.executorEnvs,
       classPathEntries, libraryPathEntries, extraJavaOpts)
     val sparkHome = sc.getSparkHome()
     val appDesc = new ApplicationDescription(sc.appName, maxCores, sc.executorMemory, command,

core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackend.scala

@@ -122,7 +122,7 @@ private[spark] class CoarseMesosSchedulerBackend(
     val extraLibraryPath = conf.getOption(libraryPathOption).map(p => s"-Djava.library.path=$p")
     val extraOpts = Seq(extraJavaOpts, extraLibraryPath).flatten.mkString(" ")
 
-    sc.testExecutorEnvs.foreach { case (key, value) =>
+    sc.executorEnvs.foreach { case (key, value) =>
       environment.addVariables(Environment.Variable.newBuilder()
         .setName(key)
         .setValue(value)

core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosSchedulerBackend.scala

@@ -90,7 +90,7 @@ private[spark] class MesosSchedulerBackend(
       "Spark home is not set; set it through the spark.home system " +
       "property, the SPARK_HOME environment variable or the SparkContext constructor"))
     val environment = Environment.newBuilder()
-    sc.testExecutorEnvs.foreach { case (key, value) =>
+    sc.executorEnvs.foreach { case (key, value) =>
       environment.addVariables(Environment.Variable.newBuilder()
         .setName(key)
         .setValue(value)