Ignore Cargo.lock for libs in cargo-new

The lockfile should only be checked in for bins, not libs.

Closes #304

src/cargo/ops/cargo_new.rs

@@ -32,7 +32,11 @@ fn mk(path: &Path, name: &str, opts: &NewOptions) -> CargoResult<()> {
 
  if opts.git {
  try!(git!("init", path));
- try!(File::create(&path.join(".gitignore")).write(b"/target\n"));
+ let mut gitignore = "/target\n".to_string();
+ if !opts.bin {
+ gitignore.push_str("/Cargo.lock\n");
+ }
+ try!(File::create(&path.join(".gitignore")).write(gitignore.as_bytes()));
  } else {
  try!(fs::mkdir(path, io::UserRWX));
  }