Smokescreen. I'm sure he's hoping that people would be wondering why he brought books with him - no matter what they were. This way, they'll be talking about that instead of the charges.
Frankly though I think he just wanted to read something while in jail.
I think he was well aware that he would be released on bail (albeit with ankle bracelet) after the arraignment. Jail may be in his future (we can hope), but that wasn't going to be today.
