Unskip volume show host test

This PS unskips volume show how test because the related bug
was fixed [0] and now the endpoint appears in the policy in code
documentation for "volume_extension:hosts" [1].

[0] I76ca1251cd14da6c777bd48a28906d8362d836b0
[1] https://github.com/openstack/cinder/blob/4ca4f644008f4c89edc472cacda19050367ba54a/cinder/policies/hosts.py

Related-Bug: #1732808
Change-Id: I5ddeb7f11d18c5e7382930aa2e05bf9c5dc1057e
1 file changed