Hardening/libcurl

**DON'T MERGE**

Orion uses libcurl to send HTTP requests.

**Edit (Fermin)**: potentially closes #442 
I think I remember why that head is there...

All the notifications are equal so I thought that just having the first one (obtained with that head) was enough and makes the test easy to debug. Those days, the notification timing was a bit unstable...

However, by the time being, I think is safer and simpler without haed, so, let's go with it.

NTC (just a reflexion :)