Comment 2 for bug 791030

I found true reason of the hangup. I will fix in today.

It seems to be needed to release s-latch of all hash indexes if someone other wait one of it.

The current implementation (If someone wait the s-latch "which the trx hold", release it only) might cause wait chain of the btr_search_latch_part[n]. only "release all" also seems not enough.