restapi: Rx and Tx should be displayed as BYTES_PER_SECOND

The rx and tx are reported and displayed in the rest as percent of the
speed. It should be converted and displayed as BYTES_PER_SECOND.

Change-Id: Icb004ae50c00acbcb7aeb53fb3962028e6966fbc
Bug-Url: https://bugzilla.redhat.com/887230
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>