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://golang.org/cl/13314044

src/pkg/go/build/deps_test.go

@@ -95,6 +95,7 @@ var pkgDeps = map[string][]string{
 	"hash/fnv":            {"L2", "hash"},
 	"image":               {"L2", "image/color"}, // interfaces
 	"image/color":         {"L2"},                // interfaces
+	"image/color/palette": {"L2", "image/color"},
 	"reflect":             {"L2"},
 
 	"L3": {
@@ -112,6 +113,7 @@ var pkgDeps = map[string][]string{
 		"hash/fnv",
 		"image",
 		"image/color",
+		"image/color/palette",
 		"reflect",
 	},
 
@@ -205,7 +207,7 @@ var pkgDeps = map[string][]string{
 	"go/build":            {"L4", "OS", "GOPARSER"},
 	"html":                {"L4"},
 	"image/draw":          {"L4"},
-	"image/gif":           {"L4", "compress/lzw", "image/draw"},
+	"image/gif":           {"L4", "compress/lzw", "image/color/palette", "image/draw"},
 	"image/jpeg":          {"L4"},
 	"image/png":           {"L4", "compress/zlib"},
 	"index/suffixarray":   {"L4", "regexp"},
@@ -231,7 +233,8 @@ var pkgDeps = map[string][]string{
 	// that shows up in programs that use cgo.
 	"C": {},
 
-	"os/user": {"L4", "CGO", "syscall"},
+	// Plan 9 alone needs io/ioutil and os.
+	"os/user": {"L4", "CGO", "io/ioutil", "os", "syscall"},
 
 	// Basic networking.
 	// Because net must be used by any package that wants to