fixing https://issues.apache.org/jira/browse/STRATOS-525 - ability to assign availability zone via NovaTemplateOptions
fixng https://issues.apache.org/jira/browse/STRATOS-470 for Openstack availability zones
fixing a bug in agent config
fixing a mistakenly added Option
Fixing error handling empty case

Signed-off-by: Udara Liyanage <udara@wso2.com>
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-stratos