minor refactering

Author: kanzhang

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

@@ -188,12 +188,11 @@ import org.apache.spark.util.Utils
 
 private[spark] class SecurityManager(sparkConf: SparkConf)
   extends Logging with SecretKeyHolder {
-  import SecurityManager._
 
   // key used to store the spark secret in the Hadoop UGI
   private val sparkSecretLookupKey = "sparkCookie"
 
-  private val authOn = sparkConf.getBoolean(SPARK_AUTH_CONF, false)
+  private val authOn = sparkConf.getBoolean(SecurityManager.SPARK_AUTH_CONF, false)
   // keep spark.ui.acls.enable for backwards compatibility with 1.0
   private var aclsOn =
     sparkConf.getBoolean("spark.acls.enable", sparkConf.getBoolean("spark.ui.acls.enable", false))
@@ -367,8 +366,8 @@ private[spark] class SecurityManager(sparkConf: SparkConf)
     } else {
       // user must have set spark.authenticate.secret config
       // For Master/Worker, auth secret is in conf; for Executors, it is in env variable
-      sys.env.get(ENV_AUTH_SECRET)
-        .orElse(sparkConf.getOption(SPARK_AUTH_SECRET_CONF)) match {
+      sys.env.get(SecurityManager.ENV_AUTH_SECRET)
+        .orElse(sparkConf.getOption(SecurityManager.SPARK_AUTH_SECRET_CONF)) match {
         case Some(value) => value
         case None => throw new Exception("Error: a secret key must be specified via the " +
           "spark.authenticate.secret config")