[MERGE][bug 140614] Fix seltest noise in _http_start

[Martin Pool]

Martin Pool has voted approve.
Status is now: Approved
Comment:
It would be nice to know why we get an error with the existing code; I 
can't see why it's wrong.  However this doesn't seem  incorrect either, 
so if it fixes the problem it's ok with me to merge it.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3Cm2odg0ndyf.fsf%40free.fr%3E