Increment Version to 2.3_r4

Bug 4588939

Change-Id: I7aca7f0bc309b4e63ff59c0c2abf0aa28cf5e008
diff --git a/tools/host/src/com/android/cts/Version.java b/tools/host/src/com/android/cts/Version.java
index 7d14552..a06891e 100644
--- a/tools/host/src/com/android/cts/Version.java
+++ b/tools/host/src/com/android/cts/Version.java
@@ -18,7 +18,7 @@
 
 public class Version {
     // The CTS version string
-    private static final String version = "2.3_r3";
+    private static final String version = "2.3_r4";
 
     private Version() {
         // no instances allowed