update the vagrant module to support ansible 2.x
When I tried to run Alluxio on EC2 through vagrant and ansible and run *./create <number of machines> aws *to launch the Alluxio cluster, many issues occurred.
Some ansible playbook keywords like sudo: yes has been deprecated and should be changed to remote_user:root; become:yes; become_method:sudo.
Some file paths cannot be targeted properly and should change the file paths.
Some other issues affect the successfully run of ./create <number of machines> aws should also be fixed.