go/build: undo CL 7129048

This broke 'godoc net/http'.

TBR=adg
CC=golang-dev
https://golang.org/cl/7235052

src/pkg/go/build/build.go

@@ -322,7 +322,9 @@ func (p *Package) IsCommand() bool {
 // the named directory.
 func (ctxt *Context) ImportDir(dir string, mode ImportMode) (*Package, error) {
 	p, err := ctxt.Import(".", dir, mode)
-	if err == nil && !ctxt.isDir(p.Dir) {
+	// TODO(rsc,adg): breaks godoc net/http. Not sure why.
+	// See CL 7232047 and issue 4696.
+	if false && err == nil && !ctxt.isDir(p.Dir) {
 		err = fmt.Errorf("%q is not a directory", p.Dir)
 	}
 	return p, err

src/pkg/go/build/build_test.go

@@ -92,6 +92,7 @@ func TestLocalDirectory(t *testing.T) {
 
 // golang.org/issue/3248
 func TestBogusDirectory(t *testing.T) {
+	return // See issue 4696.
 	const dir = "/foo/bar/baz/gopher"
 	_, err := ImportDir(dir, FindOnly)
 	want := fmt.Sprintf("%q is not a directory", filepath.FromSlash(dir))