rust-cpython: remove invalid __package__ attribute

Since mercurial.rustext is a package, its __package__ should be, if set,
"mercurial.rustext". AFAIK, we don't have to set this attribute manually
as the rustext module will be imported by the system importer.

https://stackoverflow.com/a/21233334/10435339

rust/hg-cpython/src/lib.rs

@@ -35,7 +35,6 b' py_module_initializer!(rustext, initrust'
     )?;
 
     let dotted_name: String = m.get(py, "__name__")?.extract(py)?;
-    m.add(py, "__package__", "mercurial")?;
     m.add(py, "ancestor", ancestors::init_module(py, &dotted_name)?)?;
     m.add(py, "GraphError", py.get_type::<exceptions::GraphError>())?;
     Ok(())