[SPARK-6673] spark-shell.cmd can't start in Windows even when spark was built

added equivalent script to load-spark-env.sh

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #5328 from tsudukim/feature/SPARK-6673 and squashes the following commits:

aaefb19 [Masayoshi TSUZUKI] removed dust.
be3405e [Masayoshi TSUZUKI] [SPARK-6673] spark-shell.cmd can't start in Windows even when spark was built

bin/load-spark-env.cmd

+@echo off
+
+rem
+rem Licensed to the Apache Software Foundation (ASF) under one or more
+rem contributor license agreements.  See the NOTICE file distributed with
+rem this work for additional information regarding copyright ownership.
+rem The ASF licenses this file to You under the Apache License, Version 2.0
+rem (the "License"); you may not use this file except in compliance with
+rem the License.  You may obtain a copy of the License at
+rem
+rem    http://www.apache.org/licenses/LICENSE-2.0
+rem
+rem Unless required by applicable law or agreed to in writing, software
+rem distributed under the License is distributed on an "AS IS" BASIS,
+rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+rem See the License for the specific language governing permissions and
+rem limitations under the License.
+rem
+
+rem This script loads spark-env.cmd if it exists, and ensures it is only loaded once.
+rem spark-env.cmd is loaded from SPARK_CONF_DIR if set, or within the current directory's
+rem conf/ subdirectory.
+
+if [%SPARK_ENV_LOADED%] == [] (
+  set SPARK_ENV_LOADED=1
+
+  if not [%SPARK_CONF_DIR%] == [] (
+    set user_conf_dir=%SPARK_CONF_DIR%
+  ) else (
+    set user_conf_dir=%~dp0..\..\conf
+  )
+
+  call :LoadSparkEnv
+)
+
+rem Setting SPARK_SCALA_VERSION if not already set.
+
+set ASSEMBLY_DIR2=%SPARK_HOME%/assembly/target/scala-2.11
+set ASSEMBLY_DIR1=%SPARK_HOME%/assembly/target/scala-2.10
+
+if [%SPARK_SCALA_VERSION%] == [] (
+
+  if exist %ASSEMBLY_DIR2% if exist %ASSEMBLY_DIR1% (
+    echo "Presence of build for both scala versions(SCALA 2.10 and SCALA 2.11) detected."
+    echo "Either clean one of them or, set SPARK_SCALA_VERSION=2.11 in spark-env.cmd."
+    exit 1
+  )
+  if exist %ASSEMBLY_DIR2% (
+    set SPARK_SCALA_VERSION=2.11
+  ) else (
+    set SPARK_SCALA_VERSION=2.10
+  )
+)
+exit /b 0
+
+:LoadSparkEnv
+if exist "%user_conf_dir%\spark-env.cmd" (
+  call "%user_conf_dir%\spark-env.cmd"
+)

bin/pyspark2.cmd

@@ -20,8 +20,7 @@ rem
 rem Figure out where the Spark framework is installed
 set SPARK_HOME=%~dp0..
 
-rem Load environment variables from conf\spark-env.cmd, if it exists
-if exist "%SPARK_HOME%\conf\spark-env.cmd" call "%SPARK_HOME%\conf\spark-env.cmd"
+call %SPARK_HOME%\bin\load-spark-env.cmd
 
 rem Figure out which Python to use.
 if "x%PYSPARK_DRIVER_PYTHON%"=="x" (

bin/run-example2.cmd

@@ -25,8 +25,7 @@ set FWDIR=%~dp0..\
 rem Export this as SPARK_HOME
 set SPARK_HOME=%FWDIR%
 
-rem Load environment variables from conf\spark-env.cmd, if it exists
-if exist "%FWDIR%conf\spark-env.cmd" call "%FWDIR%conf\spark-env.cmd"
+call %SPARK_HOME%\bin\load-spark-env.cmd
 
 rem Test that an argument was given
 if not "x%1"=="x" goto arg_given

bin/spark-class2.cmd

@@ -20,8 +20,7 @@ rem
 rem Figure out where the Spark framework is installed
 set SPARK_HOME=%~dp0..
 
-rem Load environment variables from conf\spark-env.cmd, if it exists
-if exist "%SPARK_HOME%\conf\spark-env.cmd" call "%SPARK_HOME%\conf\spark-env.cmd"
+call %SPARK_HOME%\bin\load-spark-env.cmd
 
 rem Test that an argument was given
 if "x%1"=="x" (