Fixes winrm access denied bug for Windows versions 6.0 and 6.1

On Windows Vista, 2008, 2008 R2 and 7, changing the configuration of
the winrm service will fail with an "Access is denied" error if the
User Account Control remote restrictions are enabled.

The solution to this issue is to temporarily disable the User
Account Control remote restrictions.

https://support.microsoft.com/kb/951016

Co-Authored-By: Robert Tingirica <rtingirica@cloudbasesolutions.com>
Closes-Bug: #1379854

Change-Id: I07b61b94900d39ad0aee544e26ee37bbc94bf7b9
Add support for OpenNebula meta-data

All the needed details are taken from a context script file
found on a ISO mounted inside the VM.