Don't use iteritems() in templar to avoid (hostvars) dict size change errors

lib/ansible/template/__init__.py

@@ -251,8 +251,10 @@ class Templar:
                 return [self.template(v, convert_bare=convert_bare, preserve_trailing_newlines=preserve_trailing_newlines, fail_on_undefined=fail_on_undefined, overrides=overrides) for v in variable]
             elif isinstance(variable, dict):
                 d = {}
-                for (k, v) in variable.iteritems():
-                    d[k] = self.template(v, convert_bare=convert_bare, preserve_trailing_newlines=preserve_trailing_newlines, fail_on_undefined=fail_on_undefined, overrides=overrides)
+                # we don't use iteritems() here to avoid problems if the underlying dict
+                # changes sizes due to the templating, which can happen with hostvars
+                for k in variable.keys():
+                    d[k] = self.template(variable[k], convert_bare=convert_bare, preserve_trailing_newlines=preserve_trailing_newlines, fail_on_undefined=fail_on_undefined, overrides=overrides)
                 return d
             else:
                 return variable