Kernel prepatch 4.9-rc4

The 4.9-rc4 kernel prepatch is out fortesting. Linus says: "So I'm not going to lie: this is not a smallrc, and I'd have been happier if it was. But it's not unreasonably largefor this (big) release either, so it's not like I'd start worrying. I'mcurrently still assuming that we'll end up with the usual seven releasecandidates, assuming things start calming down. We'll see how that goes aswe get closer to a release."