functional tests: wait for 'output' field
functional tests: wait for 'output' field

console output can be returned not in the first request by Amazon.
so tests must wait for no exception in get_console_output
and then for output field in result.

Change-Id: Iaf0549a185d2bf99dc83aea8f8272f2bf0ae5282

hayderimran7/ec2-api,stackforge/ec2-api,openstack/ec2-api,hayderimran7/ec2-api,openstack/ec2-api,stackforge/ec2-api