path/filepath: repair and simplify the symlink test I hate symlinks. Fixes issue 2787.
path/filepath: repair and simplify the symlink test
I hate symlinks.
Fixes issue 2787.

R=golang-dev, dsymonds, rsc
CC=golang-dev
http://codereview.appspot.com/5638043

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang