go/build: fix deps_test for Plan 9's os/user dependencies and to include the new image/color/palette package.
go/build: fix deps_test for Plan 9's os/user dependencies and to
include the new image/color/palette package.

R=r
CC=golang-dev
https://codereview.appspot.com/13314044

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