Update rancherd-12-monitoring-dashboard.yaml (#639)

The titles "Network Receive Bytes" and "Network Transmit Bytes" are a bit misleading as the values are in Bits/s. 
And Storage Write Traffic Bytes" is really in Bytes/s. See expr :" metrics* 8!" The units was already correctly shown in "MB/s".

pkg/config/templates/rancherd-12-monitoring-dashboard.yaml

@@ -497,7 +497,7 @@ resources:
             "timeFrom": null,
             "timeRegions": [],
             "timeShift": null,
-            "title": "Network Receive Bytes",
+            "title": "Network Receive Bits",
             "tooltip": {
               "shared": true,
               "sort": 0,
@@ -592,7 +592,7 @@ resources:
             "timeFrom": null,
             "timeRegions": [],
             "timeShift": null,
-            "title": "Network Transmit Bytes",
+            "title": "Network Transmit Bits",
             "tooltip": {
               "shared": true,
               "sort": 0,