1 transfer with a minimum speed of 128 Bytes was a nice try but it is
way too low. Even a pi3 was able to handle 7 grpc transfers. We have 4
satellites and with 5 concurrent transfers that should be a total of 20
concurrent transfers. Each transfer will have a minimum speed of 5KB/s.
That should give us a better througput and still be Ok on a pi3.
Change-Id: I650a7baf890080901ef70ea3b5636d93009b4e60
