ec2-release: check image format before upload

EC2 doesn't support image formats other than raw. However it does
not verify image format before upload so qcow2 image may be successfully
imported as a volume and attached to an instance. Instance with such a volume
will fail to start and there will be no indication of what went wrong.

Image format verification added to the ec2-release.sh script to eliminate
such a possibility.

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
release-ec2: make credentials management more robust

This patch introduces 2 changes:

  1. fix help text to make instructions on credentials definition clearer
  2. verify credentials presence before starting the release process

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
release-ec2: move generic code to separate file

Generic EC2-related code moved to a separate file to be reused
in Jenkins test automation scripts.

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
ec2-utils: introduce more instance-related functions

Functions introduced:

  1. Query instance ID by name
  2. Query instance private IP by name
temp script for jenkins/tomcat