No need to generate ssh key pair for ansibler on each host.

We are already uploading a public key for ansibler on each host, which
implies we have the private key required required for access already,
so generating a new key pair on each host is unnecessary.
Python requirements, ready for pip-ing.

Helpful when using within a virtualenv. Boto is needed the ansible EC2
dynamic inventory plugin. Keyczar is needed for ansible’s accelerate mode.
The bootstrap playbook can now be used with EC2 dynamic inventory, too.

With EC2 instances whose addresses change constantly, a static inventory
file is not suitable. ansible’s ec2.py plugin allows the use of dynamic
inventory data from AWS. The new bootstrap-ec2.sh bash script allows the
user to pass through the AWS group name (can be a security group, tag,
etc.) of the machine that need to be bootstrapped.
Generate hosts file lines from bootstrapped EC2 instance metadata.

Despite the dynamic nature of EC2 instances, we still want to be able to
access them from the local host during their lifetime. Adding the
bootstrapped hosts to our /etc/hosts is a simple way of achieving this.
Fix smokeping role for Ubuntus older than 13.10.

Looks like ‘sendmail’ is not installed by default on the amazon AMI of ubuntu
so also added that as a dep.
Turn on back refs when using lineinfile to make sure only replacements happen, not additions

Seems this is some weird behaviour in lineinfile, which results in
multiple runs of the plays to add the same line to the end of the file
when the regexp is not found. Discussion here:
https://groups.google.com/d/msg/ansible-project/XmaC_YHWh00/M3VBdwzU_hEJ
Restarting hue seems to work fine without this actually - the playbook contains a ‘sudo: true’ anyway.
Point to a default location for the ‘ansibler’ user’s private key