Fixing Spark distro (#30)

Author: akshaisarma

docs/quick-start/spark.md

@@ -88,7 +88,7 @@ We will run the bullet-spark backend using [Spark 2.2.1](https://spark.apache.or
 ```bash
 export BULLET_SPARK=$BULLET_HOME/backend/spark
 cd $BULLET_SPARK
-curl -O http://www-eu.apache.org/dist/spark/spark-2.2.1/spark-2.2.1-bin-hadoop2.7.tgz
+curl -O https://archive.apache.org/dist/spark/spark-2.2.1/spark-2.2.1-bin-hadoop2.7.tgz
 tar -xzf spark-2.2.1-bin-hadoop2.7.tgz
 ```
 

examples/install-all-spark.sh

@@ -171,7 +171,7 @@ launch_web_service() {
 
 install_spark() {
     println "Downloading Spark version ${SPARK_VERSION}..."
-    download "http://www-us.apache.org/dist/spark/spark-${SPARK_VERSION}" "${SPARK_DISTRO}.tgz"
+    download "https://archive.apache.org/dist/spark/spark-${SPARK_VERSION}" "${SPARK_DISTRO}.tgz"
 
     println "Installing Spark version ${SPARK_VERSION}..."
     cp ${BULLET_DOWNLOADS}/${SPARK_DISTRO}.tgz ${BULLET_SPARK}/