I have problem with XWalkRuntimeClientVersion [Android]

I have a problem when is called this function

```java
 public static String getVersion() {
        return XWalkRuntimeClientVersion.XWALK_RUNTIME_CLIENT_VERSION;
    }
```
So, I add this file XWalkRuntimeClientVersion.java (template) that contains
```java
package org.xwalk.app.runtime;

interface XWalkRuntimeClientVersion {
    // The version will be generated by a script. Be careful to change the string.
    // See build/android/generate_runtime_client_version.py for details.
    public static final String XWALK_RUNTIME_CLIENT_VERSION = "TO_BE_REPLACED_BY_PYTHON_SCRIPT";
}
```
If I run that, the app require update the runtime app (crosswalk)
If I delete of code to verify version of runtine it's works...
I don't know what is my problem if I use the last version Runtine library