Although I wasn't clear on whether the URL you provided was the MyGet equivalent of the symbol server URL, I attempted to use it as a symbol server. VS 2015 ended up making the following request:
But after just over 3.5 minutes the following response was sent:
...
<b> Description: </b>HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.
<br><br>
<b> Requested URL: </b>/MyGet/Metadata/autofac/Autofac.Integration.WebApi.pdb/9E6C81F1C6D3427AADFC1CD0FC76213C1/Autofac.Integration.WebApi.pd_<br><br>
...
On a different note, the MyGet page for Autofac is still referencing all the older URLs (e.g.,Google Code instead of Github):
Thank you for all your work on Autofac.
--Kaleb