schema: do not validate unrequested params in command_defaults

Request specific params when getting the defaults instead of getting
defaults for all params and filtering the result.

This fixes command_defaults failing with validation errors on unrequested
params.

https://fedorahosted.org/freeipa/ticket/4739

Reviewed-By: David Kupka <dkupka@redhat.com>

ipalib/frontend.py

@@ -670,7 +670,7 @@ class Command(HasParam):
             if kw.get(param.name, None) is None:
                 continue
 
-    def get_default(self, **kw):
+    def get_default(self, _params=None, **kw):
         """
         Return a dictionary of defaults for all missing required values.
 
@@ -687,8 +687,10 @@ class Command(HasParam):
         >>> c.get_default(color=u'Yellow')
         {}
         """
-        params = [p.name for p in self.params() if p.name not in kw and (p.required or p.autofill)]
-        return dict(self.__get_default_iter(params, kw))
+        if _params is None:
+            _params = [p.name for p in self.params()
+                       if p.name not in kw and (p.required or p.autofill)]
+        return dict(self.__get_default_iter(_params, kw))
 
     def get_default_of(self, _name, **kw):
         """

ipaserver/plugins/schema.py

@@ -229,8 +229,7 @@ class command_defaults(PKQuery):
             raise errors.ConversionError(name=name,
                                          error=_("must be a dictionary"))
 
-        result = command.get_default(**kw)
-        result = {n: v for n, v in result.items() if n in params}
+        result = command.get_default(params, **kw)
 
         return dict(result=result)