message: daemon: include profile and rustc version into build-time info
  So we can have formatted version info like:
  ```
  Version: 	0.1.0
  Git Commit:
  Build Time: 	Mon, 09 Nov 2020 07:46:25 +0000
  Profile: 	release
  Rustc: 		rustc 1.47.0 (18bf6b4f0 2020-10-07)
  ```
diff: @@ -128,16 +128,8 @@ fn get_readahead_files(source: &Path) -> Result<BTreeMap<PathBuf, Option<u64>>>
  Ok(files)
  }
  -pub mod built_info {
  - include!(concat!(env!("OUT_DIR"), "/built.rs"));
  -}
  -
  fn main() -> Result<()> {
  - let bti: String = BuildTimeInfo::dump(
  - crate_version!(),
  - built_info::GIT_COMMIT_HASH.unwrap_or_default(),
  - built_info::BUILT_TIME_UTC,
  - );
  + let bti: String = BuildTimeInfo::dump(crate_version!());
  let cmd = App::new("nydus image builder")
  .version(bti.as_str())
  