CHANGELOG: updates for v0.9.16 release

Update the changelog for a v0.9.15 release

In CentOS `wget` does not exist by default. And when it is not there,…

… the or logic does not work as wanted. (fpco#309)

Bugfix: module init-snippet-attach-ebs-volume

In CentOS `wget` does not exist by default. And when it is not there, the or logic does not work as wanted.

add official centos web page comment to module

Add the v0.9.12 release tag

CHANGELOG: update for v0.9.9