Allow delegate_to on a role again

Fixes #12560

lib/ansible/playbook/role/__init__.py

@@ -65,6 +65,8 @@ def hash_params(params):
 
 class Role(Base, Become, Conditional, Taggable):
 
+    _delegate_to = FieldAttribute(isa='string')
+
     def __init__(self, play=None):
         self._role_name        = None
         self._role_path        = None

lib/ansible/playbook/role/include.py

@@ -38,6 +38,8 @@ class RoleInclude(RoleDefinition):
     FIXME: docstring
     """
 
+    _delegate_to          = FieldAttribute(isa='string')
+
     def __init__(self, play=None, role_basedir=None, variable_manager=None, loader=None):
         super(RoleInclude, self).__init__(play=play, role_basedir=role_basedir, variable_manager=variable_manager, loader=loader)