Verify the response attributes of 'show_host_detail'

This patch verifies the response attributes of 'show_host_detail'.
The response body of v2 and v3 API has the same format:

"host": [
{
"resource": {
"cpu": 1,
"disk_gb": 1028,
"host": "5ca60c6792a1442f9471ff575443f94d",
"memory_mb": 8192,
"project": "(total)"
}
}
]

Partially implements blueprint nova-api-attribute-test
Change-Id: I1b9e698a97d487541abb26aea10fa20e79448f84
Merge "Verify the response attributes of 'show_host_detail'"
Merge branch 'master' of https://github.com/openstack/tempest