Refactor calls for gathering physical server stats

This patch simplifies the formal parameters of the methods that
are in charge of gathering the means to obtain actual values of
the stats tested in an integration test.

wrapanapi/systems/lenovo.py

@@ -348,23 +348,31 @@ def set_server_led_blinking(self, server_name):
 
         return "LED state action has been sent, status:" + str(response.status_code)
 
-    def server_stats(self, *requested_stats, **kwargs):
-        # Get the requester which represents the class of this method's caller
-        requester = kwargs.get('requester')
-
+    def server_stats(self, physical_server, requested_stats, **kwargs):
+        """
+        Obtain the means to compute the requested physical server statistics.
+
+        Args:
+          physical_server: representation for the class of this method's caller
+          requested_stats: the statistics to be obtained
+        """
         # Retrieve and return the stats
         requested_stats = requested_stats or self._stats_available
 
-        return {stat: self._server_stats_available[stat](self, requester)
+        return {stat: self._server_stats_available[stat](self, physical_server)
                 for stat in requested_stats}
 
-    def server_inventory(self, *requested_items, **kwargs):
-        # Get the requester which represents the class of this method's caller
-        requester = kwargs.get('requester')
+    def server_inventory(self, physical_server, requested_items, **kwargs):
+        """
+        Obtain the means to compute the requested physical server inventory.
 
+        Args:
+          physical_server: representation for the class of this method's caller
+          requested_items: the inventory items to be obtained for the server
+        """
         # Retrieve and return the inventory
         requested_items = requested_items or self._server_inventory_available
-        return {item: self._server_inventory_available[item](self, requester)
+        return {item: self._server_inventory_available[item](self, physical_server)
                 for item in requested_items}
 
     def get_network_devices(self, server_name):