Shell script for creating AMI's.

This installs all the necessary packages and configuration starting with an
Amazon AMI. Tested with Amazon Linux AMI 2014.03.2.
btw i think this doesn't work because httpd by default installs httpd 2.2.x, which conflicts with ganglia.

we should remove httpd, and then just install ganglia-web (which will bring in a transitive dependency on httpd 2.4).