Remove debug code

Author: lidizheng

noxfile.py

@@ -146,8 +146,6 @@ def showcase_unit(
 
     # Install a client library for Showcase.
     with tempfile.TemporaryDirectory() as tmp_dir:
-        tmp_dir = '/Users/lidiz/playground/gapic-showcase/dest'
-
         # Download the Showcase descriptor.
         session.run(
             'curl', 'https://github.com/googleapis/gapic-showcase/releases/'