Change docstring of compute client

We need to put the links to api-site for explaining what parameters
can be passed to Nova, then this patch adds them.
In addition, this patch changes docstring for the consistency.

NOTE: This patch changes the methods which call "/servers" only.
      The other methods like "/servers/<id>/action/" will be changed
      with the other patches because servers_client is big and it is
      difficult to change/review all of them in a single patch.

Partially implements blueprint consistent-service-method-names

Change-Id: I36b94d6b9f136ca65cb361a8af65966f21b86b03
diff --git a/tempest/services/compute/json/servers_client.py b/tempest/services/compute/json/servers_client.py
index c71a193..aa9e6c6 100644
--- a/tempest/services/compute/json/servers_client.py
+++ b/tempest/services/compute/json/servers_client.py
@@ -32,7 +32,10 @@
         self.enable_instance_password = enable_instance_password
 
     def create_server(self, **kwargs):
-        """Create server
+        """Create server.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-compute-v2.1.html#createServer
 
         Most parameters except the following are passed to the API without
         any changes.
@@ -69,7 +72,10 @@
         return service_client.ResponseBody(resp, body)
 
     def update_server(self, server_id, **kwargs):
-        """Update server
+        """Update server.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-compute-v2.1.html#updateServer
 
         Most parameters except the following are passed to the API without
         any changes.
@@ -85,20 +91,26 @@
         return service_client.ResponseBody(resp, body)
 
     def show_server(self, server_id):
-        """Get server details"""
+        """Get server details."""
         resp, body = self.get("servers/%s" % server_id)
         body = json.loads(body)
         self.validate_response(schema.get_server, resp, body)
         return service_client.ResponseBody(resp, body)
 
     def delete_server(self, server_id):
-        """Delete server"""
+        """Delete server."""
         resp, body = self.delete("servers/%s" % server_id)
         self.validate_response(schema.delete_server, resp, body)
         return service_client.ResponseBody(resp, body)
 
     def list_servers(self, detail=False, **params):
-        """List servers"""
+        """List servers.
+
+        Available params: see http://developer.openstack.org/
+                              api-ref-compute-v2.1.html#listServers
+                          and http://developer.openstack.org/
+                              api-ref-compute-v2.1.html#listDetailServers
+        """
 
         url = 'servers'
         _schema = schema.list_servers