set __cdist_manifest for use in type emulator

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>

lib/cdist/core/manifest.py

@@ -83,6 +83,7 @@ class Manifest(object):
         return self.local.run_script(script, env=env)
 
     def run_type_manifest(self, cdist_object):
+        script = os.path.join(self.local.type_path, cdist_object.type.manifest_path)
         env = os.environ.copy()
         env.update(self.env)
         env.update({
@@ -90,6 +91,6 @@ class Manifest(object):
             '__object_id': cdist_object.object_id,
             '__object_fq': cdist_object.path,
             '__type': cdist_object.type.absolute_path,
+            '__cdist_manifest': script,
         })
-        script = os.path.join(self.local.type_path, cdist_object.type.manifest_path)
         return self.local.run_script(script, env=env)