IpConnectivity metrics: add version number

This patch adds a version field to ipconnectivity.proto and populates it
to 2, which is the logical version number for NYC-MR2.

Test: IpConnectivity{EventBuilder,Metrics}Test pass
Bug: 32127906
Change-Id: I1439f012b7f9b4211d5d5429c274ad03d2ac9d6b
diff --git a/services/core/java/com/android/server/connectivity/IpConnectivityMetrics.java b/services/core/java/com/android/server/connectivity/IpConnectivityMetrics.java
index 28e724c..85c4303 100644
--- a/services/core/java/com/android/server/connectivity/IpConnectivityMetrics.java
+++ b/services/core/java/com/android/server/connectivity/IpConnectivityMetrics.java
@@ -40,6 +40,13 @@
     private static final String TAG = IpConnectivityMetrics.class.getSimpleName();
     private static final boolean DBG = false;
 
+    // The logical version numbers of ipconnectivity.proto, corresponding to the
+    // "version" field of IpConnectivityLog.
+    private static final int NYC      = 0;
+    private static final int NYC_MR1  = 1;
+    private static final int NYC_MR2  = 2;
+    public static final int VERSION   = NYC_MR2;
+
     private static final String SERVICE_NAME = IpConnectivityLog.SERVICE_NAME;
 
     // Default size of the event buffer. Once the buffer is full, incoming events are dropped.