thirdparty: don't make zope a namespace package

There are a gazillion zope.* packages in the wild. So zope/__init__.py
needs to be a namespace package. But in Mercurial, we have 1 zope
package. And even if we had multiple packages, they'd all be in
thirdparty/zope/. So we don't need a namespace package.

Differential Revision: https://phab.mercurial-scm.org/D2929

mercurial/thirdparty/zope/__init__.py

@@ -1,7 +0,0 b''
-# this is a namespace package
-try:
-    import pkg_resources
-    pkg_resources.declare_namespace(__name__)
-except ImportError:
-    import pkgutil
-    __path__ = pkgutil.extend_path(__path__, __name__)