Change hadoop/kmeans parameters, fix timeout in vCloud Director plugin

1. Add hadoop application parameter for SAMPLES_PER_INPUTFILE and adjust calculation for NUM_OF_SAMPLES
2. Fix typo in vcloud director plug-in defaults that referred to EC2
3. Add additional debug messaging for vcloud director plugin
4. In vcloud director plugin, when deleting a VM, check whether VM creation occurred before sending delete request.
5. In vcloud director plugin, when retrying certain commands, re-connect to the vcloud director API to obtain new credentials in case the existing ones have timed out