[gnome-system-monitor] Fix displayed network transfer rates

[Robert Roth <robertroth src gnome org>]

commit c031de0a3469faf5020768de506c6169e1e71ac0
Author: Michael Hudson-Doyle <michael hudson canonical com>
Date:   Fri Feb 21 20:02:31 2020 +1300

    Fix displayed network transfer rates
    
    g_get_monotonic_time works in microseconds...

 src/load-graph.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/load-graph.cpp b/src/load-graph.cpp
index 96f63970..d5b0ebe9 100644
--- a/src/load-graph.cpp
+++ b/src/load-graph.cpp
@@ -646,7 +646,7 @@ get_net (LoadGraph *graph)
 
     if (in >= graph->net.last_in && out >= graph->net.last_out && graph->net.time != 0) {
         float dtime;
-        dtime = time - graph->net.time;
+        dtime = (time - graph->net.time) / G_USEC_PER_SEC;
         din   = static_cast<guint64>((in  - graph->net.last_in)  / dtime);
         dout  = static_cast<guint64>((out - graph->net.last_out) / dtime);
     } else {