py3: update Rust hgcommands code to pass argv to python as Str

Summary:
Update the Rust hgcommands code to pass the command line arguments into the
Python logic as `Str` types, so that this will be Unicode `str` objects when
using Python 3.

Reviewed By: xavierd

Differential Revision: D19596739

fbshipit-source-id: 7cdfd44a1c4ce8b0f86d20b634d9b27eab822b2d

eden/scm/lib/hgcommands/src/hgpython.rs

@@ -92,7 +92,7 @@ impl HgPython {
                 None => fout.clone_ref(py),
                 Some(ref error) => write_to_py_object(py, error),
             };
-            let args: Vec<Bytes> = args.into_iter().map(Bytes::from).collect();
+            let args: Vec<Str> = args.into_iter().map(Str::from).collect();
             (args, fin, fout, ferr).to_py_object(py)
         };
         entry_point_mod.call(py, "run", call_args, None)?;