message: Fix build error introduced in r334498
  Some gcc versions (circa 4.9) do not accept initializing Expected
  objects containing a reference to a function from a function.
  Change the Expected object to contain function pointers to work around
  this.
diff: @@ -161,7 +161,7 @@ static Error findVariables(lldb_private::Module &Module);
  static Error dumpModule(lldb_private::Module &Module);
  static Error verify(lldb_private::Module &Module);
  -static Expected<Error (&)(lldb_private::Module &)> getAction();
  +static Expected<Error (*)(lldb_private::Module &)> getAction();
  static int dumpSymbols(Debugger &Dbg);
  }
  @@ -494,7 +494,7 @@ Error opts::symbols::verify(lldb_private::Module &Module) {
  return Error::success();
  }
  -Expected<Error (&)(lldb_private::Module &)> opts::symbols::getAction() {
  +Expected<Error (*)(lldb_private::Module &)> opts::symbols::getAction() {
  if (Verify) {
  if (Find != FindType::None)
  return make_string_error(
  