[MINOR] Add 1.3, 1.3.1 to master branch EC2 scripts

cc pwendell

P.S: I can't believe this was outdated all along ?

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes apache#6215 from shivaram/update-ec2-map and squashes the following commits:

ae3937a [Shivaram Venkataraman] Add 1.3, 1.3.1 to master branch EC2 scripts

Author: shivaram

ec2/spark_ec2.py

@@ -48,7 +48,7 @@
     from urllib.request import urlopen, Request
     from urllib.error import HTTPError
 
-SPARK_EC2_VERSION = "1.2.1"
+SPARK_EC2_VERSION = "1.3.1"
 SPARK_EC2_DIR = os.path.dirname(os.path.realpath(__file__))
 
 VALID_SPARK_VERSIONS = set([
@@ -65,6 +65,8 @@
     "1.1.1",
     "1.2.0",
     "1.2.1",
+    "1.3.0",
+    "1.3.1",
 ])
 
 SPARK_TACHYON_MAP = {
@@ -75,6 +77,8 @@
     "1.1.1": "0.5.0",
     "1.2.0": "0.5.0",
     "1.2.1": "0.5.0",
+    "1.3.0": "0.5.0",
+    "1.3.1": "0.5.0",
 }
 
 DEFAULT_SPARK_VERSION = SPARK_EC2_VERSION