analysis.linux.ui: Make disk io display read before write

analysis.linux.ui: Make disk io display read before write

This is more inline with the typical views of hard disk usage.

An added bonus is that reads are blue and writes are red. It is better
to avoid red/green for accessibility reasons, and typically red == write.

Change-Id: I7397fdd72539646ba2fbe79f8258580bb45908d0
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/70779
Reviewed-by: Hudson CI
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>