The rate value is converted to bytes per second before being
sent to Pyroute2, but it used the wrong value for the calculations.
This resulted in incorrect rates.
It should be multiplied by 1000 (kbit), not 1024 (Kibit).
The same applies to the burst value (kb).
Change-Id: I70cb1fe651a50b2f6495d7a365a6beb2ba111c6d
Closes-Bug: #1884273
(cherry picked from commit 94d6e38fa0)