Bump libcompose and sync dependencies

vendor/github.com/godbus/dbus/transport_unixcred_linux.go

@@ -1,25 +0,0 @@
-// The UnixCredentials system call is currently only implemented on Linux
-// http://golang.org/src/pkg/syscall/sockcmsg_linux.go
-// https://golang.org/s/go1.4-syscall
-// http://code.google.com/p/go/source/browse/unix/sockcmsg_linux.go?repo=sys
-
-package dbus
-
-import (
-	"io"
-	"os"
-	"syscall"
-)
-
-func (t *unixTransport) SendNullByte() error {
-	ucred := &syscall.Ucred{Pid: int32(os.Getpid()), Uid: uint32(os.Getuid()), Gid: uint32(os.Getgid())}
-	b := syscall.UnixCredentials(ucred)
-	_, oobn, err := t.UnixConn.WriteMsgUnix([]byte{0}, b, nil)
-	if err != nil {
-		return err
-	}
-	if oobn != len(b) {
-		return io.ErrShortWrite
-	}
-	return nil
-}