Add test_can_create_server_with_a_personality_file
Finish storage volume tests and add some codes to complete the V2 version test
Add a missing volume test about volume detaching from a specified instance
Merge pull request #6 from snowsun/master

Add test_can_create_server_with_a_personality_file
Finish storage volume tests and add some codes to complete the V2 version test
Add a missing volume test about volume detaching from a specified instance