Update CTS Version to 3.1 R5

Change-Id: Ie73a39c465bd4661d50366b7c35ac87db8a8270f
diff --git a/tools/host/src/com/android/cts/Version.java b/tools/host/src/com/android/cts/Version.java
index 3a27f0f..e2280d61 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 = "3.1_r4";
+    private static final String version = "3.1_r5";
 
     private Version() {
         // no instances allowed