Added testcase for EUCA-4329 to confirm fix.

Testcase has ```--instance_dns``` option to enable changing bootstrap.webservices.use_instance_dns value.  Example of test being executed:

```
./testcases/cloud_admin/3-3/Euca4329.py --instance_dns false --config=../dev-cloud 
--password foobar --emi emi-87863A07 --instance-user ec2-user
```

This case was developed to test the metadata service for the following  meta-data attributes:

* local-hostname
* hostname

After confirming that they are available, per AWS behavior, they are compared to each other to make sure they match in value.