message: Fix usage text for cargo install
  The current text was accidentally copied from `cargo init`.
diff: @@ -6,7 +6,7 @@ use cargo::util::ToUrl;
  pub fn cli() -> App {
  subcommand("install")
  - .about("Create a new cargo package in an existing directory")
  + .about("Install a Rust binary")
  .arg(Arg::with_name("crate").multiple(true))
  .arg(
  opt("version", "Specify a version to install from crates.io")
  