fix return type of nativeSetDebugFlags

Author: greenrobot

objectbox-java/src/main/java/io/objectbox/BoxStore.java

@@ -133,7 +133,7 @@ static native void nativeRegisterCustomType(long store, int entityId, int proper
 
  static native String nativeStartObjectBrowser(long store, String urlPath, int port);
 
- static native String nativeSetDebugFlags(long store, int debugFlags);
+ static native void nativeSetDebugFlags(long store, int debugFlags);
 
  public static native boolean isObjectBrowserAvailable();