fix createHealthCheck type

Author: stephenplusplus

lib/compute/index.js

@@ -272,8 +272,8 @@ Compute.prototype.createFirewall = function(name, config, callback) {
  *     `options.timeoutSec`)
  * @param {function=} callback - The callback function.
  * @param {?error} callback.err - An error returned while making this request.
- * @param {module:compute/network} callback.network - The created Network
- *     object.
+ * @param {module:compute/health-check} callback.healthCheck - The created
+ *     HealthCheck object.
  * @param {module:compute/operation} callback.operation - An operation object
  *     that can be used to check the status of the request.
  * @param {object} callback.apiResponse - The full API response.