Increment Version to 2.2_r4

Bug 3166146

Change-Id: Ia4cd623e2c19657916748412c6024a1c93078866
diff --git a/tools/host/src/com/android/cts/Version.java b/tools/host/src/com/android/cts/Version.java
index 4664a3e..c1b5d39 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 = "2.2_r3";
+    private static final String version = "2.2_r4";
 
     private Version() {
         // no instances allowed