Ensure monasca agents report a useful user-agent
Ensure monasca agents report a useful user-agent

Instead of reporting the generic httplib/1.1 report the name of the program.

Change-Id: I1c8e144616f77035e406bc095a0f3972ab4bda0d

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent