Update ec2-scripts.md

Change spark-version from 1.1.0 to 1.2.0 in the example for spark-ec2/Launch Cluster.

Author: Miguel Peralvo <miguel.peralvo@gmail.com>

Closes #4300 from MiguelPeralvo/patch-1 and squashes the following commits:

38adf0b [Miguel Peralvo] Update ec2-scripts.md
1850869 [Miguel Peralvo] Update ec2-scripts.md

docs/ec2-scripts.md

@@ -52,7 +52,7 @@ identify machines belonging to each cluster in the Amazon EC2 Console.
     ```bash
     export AWS_SECRET_ACCESS_KEY=AaBbCcDdEeFGgHhIiJjKkLlMmNnOoPpQqRrSsTtU
 export AWS_ACCESS_KEY_ID=ABCDEFG1234567890123
-./spark-ec2 --key-pair=awskey --identity-file=awskey.pem --region=us-west-1 --zone=us-west-1a --spark-version=1.1.0 launch my-spark-cluster
+./spark-ec2 --key-pair=awskey --identity-file=awskey.pem --region=us-west-1 --zone=us-west-1a launch my-spark-cluster
     ```
 
 -   After everything launches, check that the cluster scheduler is up and sees