ENYO-3101: Check if rendering in progress is the the one expected for the opened file

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-3101, https://enyojs.atlassian.net/browse/ENYO-3180

NB: beware of GitHub branch, this is ENYO-3101-1

* fix a small regression introduced with PR related to JIRA https://enyojs.atlassian.net/browse/ENYO-2407
* Allow to show the designer rendering if the rendering in progress is the one expected by the current opened file

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com