SPARK-3259 - User data should be given to the master

Author: Allan Douglas R. de Oliveira <allan@chaordicsystems.com>

Closes #2162 from douglaz/user_data_master and squashes the following commits:

10d15f6 [Allan Douglas R. de Oliveira] Give user data also to the master

ec2/spark_ec2.py

@@ -458,7 +458,8 @@ def launch_cluster(conn, opts, cluster_name):
                                placement=opts.zone,
                                min_count=1,
                                max_count=1,
-                               block_device_map=block_map)
+                               block_device_map=block_map,
+                               user_data=user_data_content)
         master_nodes = master_res.instances
         print "Launched master in %s, regid = %s" % (zone, master_res.id)