FlowEntry must not be modified outside store.

- Remove set method from FlowEntry
- Storing last seen timestamp for FlowEntry eviction locally on FlowManager.
  FlowEntry eviction based on packet counter will take longer time to timeout
  after master Node change.

Change-Id: I7134d698dd5b9bf7cca379c5ba7c4fbcc2e3d5f3
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/FlowEntry.java b/core/api/src/main/java/org/onlab/onos/net/flow/FlowEntry.java
index 882c9df..cdccaa9 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/FlowEntry.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/FlowEntry.java
@@ -65,6 +65,7 @@
      */
     long bytes();
 
+    // TODO: consider removing this attribute
     /**
      * When this flow entry was last deemed active.
      * @return epoch time of last activity
@@ -72,35 +73,6 @@
     long lastSeen();
 
     /**
-     * Sets the last active epoch time.
-     */
-    void setLastSeen();
-
-    /**
-     * Sets the new state for this entry.
-     * @param newState new flow entry state.
-     */
-    void setState(FlowEntryState newState);
-
-    /**
-     * Sets how long this entry has been entered in the system.
-     * @param life epoch time
-     */
-    void setLife(long life);
-
-    /**
-     * Number of packets seen by this entry.
-     * @param packets a long value
-     */
-    void setPackets(long packets);
-
-    /**
-     * Number of bytes seen by this rule.
-     * @param bytes a long value
-     */
-    void setBytes(long bytes);
-
-    /**
      * Indicates the error type.
      * @return an integer value of the error
      */