handle enums that are explicitly provided and within a provided namespace.

[rkirov]

The following pattern while highly suspicious is valid Closure:

goog.provide('goog.A');
goog.provide('goog.A.B');

/** @constructor */
goog.A = function() {}

/** @enum */
goog.A.B = {};

The current code will create a var for B in goog.A, and also declare namespace goog.A.B which is an error.

see: https://github.com/google/closure-library/blob/master/closure/goog/fx/transition.js