Fix volume v1 api ref links

This PS fixes missing or broken volume v1 api-ref links.
Many links like [0] are "broken": they don't actually take
you to any page with information specific to that endpoint.
These broken links have been substituted with the v2 api
ref version, as it is the nearest version to v1 that is
not broken.

Other links that were missing have been included from the v2
api ref as well.

[0] http://developer.openstack.org/api-ref-blockstorage-v1.html#updateQuota

Change-Id: I79407238a9bd68c34c360fd8e3e214ec4c0cb1db
diff --git a/tempest/lib/services/volume/v1/hosts_client.py b/tempest/lib/services/volume/v1/hosts_client.py
index 56ba12c..9b19b84 100644
--- a/tempest/lib/services/volume/v1/hosts_client.py
+++ b/tempest/lib/services/volume/v1/hosts_client.py
@@ -23,8 +23,12 @@
     """Client class to send CRUD Volume Host API V1 requests"""
 
     def list_hosts(self, **params):
-        """Lists all hosts."""
+        """Lists all hosts.
 
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://developer.openstack.org/api-ref/block-storage/v2/#list-all-hosts
+        """
         url = 'os-hosts'
         if params:
             url += '?%s' % urllib.urlencode(params)