OpenFlow: use same timer throughout all component lifetime

Calls to the modified methods (all configuration changes through the
CLI, for example) of OpenFlowDeviceProvider and OpenFlowRuleProvider
cause a switch from executor to another one on PortStatsCollector and
FlowStats collector respectively.

Since these Collectors are constructed with a Timer argument, we might
as well use those timers properly right away.

Change-Id: I32aa8c89d9615ea065e5fd9fd7dfc70da96b9739
diff --git a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
index 8aa509d..a4098fa 100644
--- a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
+++ b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
@@ -162,7 +162,7 @@
     label = "Frequency (in seconds) for polling switch Port statistics")
     private int portStatsPollFrequency = POLL_INTERVAL;
 
-    private final Timer timer = new Timer("onos-openflow-collector");
+    private final Timer timer = new Timer("onos-openflow-portstats-collector");
 
     private HashMap<Dpid, PortStatsCollector> collectors = Maps.newHashMap();