update pEp engine revision

(grafted from 7a1b9d7460640b053599f94607cf166599af141c)

android/src/org/pEp/jniadapter/AndroidHelper.java

@@ -29,7 +29,7 @@ public class AndroidHelper {
     private static File tmpDir;
         
     // TODO : Increment when needed.
-    public static int ENGINE_VERSION_CODE = 1669;
+    public static int ENGINE_VERSION_CODE = 1686;
 
     private static File shareDir;