Simplify diagnose mangling/unmangling functions

The functions in ganeti-noded and rpc.py still deal with the fact that an
InvalidOS error could be returned by DiagnoseOS. As this is not the case
anymore simplify their code for the current behavior.

Reviewed-By: iustinp

daemons/ganeti-noded

@@ -451,23 +451,7 @@ class ServerObject(pb.Avatar):
     """Query detailed information about existing OSes.
 
     """
-    os_list = backend.DiagnoseOS()
-    if not os_list:
-      # this catches also return values of 'False',
-      # for which we can't iterate over
-      return os_list
-    result = []
-    for data in os_list:
-      if isinstance(data, objects.OS):
-        result.append(data.ToDict())
-      elif isinstance(data, errors.InvalidOS):
-        result.append(data.args)
-      else:
-        raise errors.ProgrammerError("Invalid result from backend.DiagnoseOS"
-                                     " (class %s, %s)" %
-                                     (str(data.__class__), data))
-
-    return result
+    return [os.ToDict() for os in backend.DiagnoseOS()]
 
   @staticmethod
   def perspective_os_get(params):

lib/rpc.py

@@ -638,17 +638,10 @@ def call_os_diagnose(node_list):
   result = c.getresult()
   new_result = {}
   for node_name in result:
-    nr = []
     if result[node_name]:
-      for data in result[node_name]:
-        if data:
-          if isinstance(data, dict):
-            nr.append(objects.OS.FromDict(data))
-          elif isinstance(data, tuple) and len(data) == 3:
-            nr.append(errors.InvalidOS(data[0], data[1], data[2]))
-          else:
-            raise errors.ProgrammerError("Invalid data from"
-                                         " xcserver.os_diagnose")
+      nr = [objects.OS.FromDict(oss) for oss in result[node_name]]
+    else:
+      nr = []
     new_result[node_name] = nr
   return new_result