Bluetooth: Update the sdk version

As GST test fails, update the SDk version to 23.

Change-Id: Ief58b29a97eae8dbc7d5ba7166e7c76311b38266
diff --git a/bttestapp/AndroidManifest.xml b/bttestapp/AndroidManifest.xml
index f9fc12b..35f8bba 100644
--- a/bttestapp/AndroidManifest.xml
+++ b/bttestapp/AndroidManifest.xml
@@ -13,7 +13,7 @@
 
     <uses-sdk
         android:minSdkVersion="17"
-        android:targetSdkVersion="17" />
+        android:targetSdkVersion="23" />
 
     <application
         android:allowBackup="true"