sort: fix computation of maxDepth to avoid infinite loop
sort: fix computation of maxDepth to avoid infinite loop

The current computation loops indefinitely if n > 1<<30 (for 32-bit ints).

R=golang-dev, gri
CC=golang-dev
http://codereview.appspot.com/5848067

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang