python-builder: drop # from line

If the extras includes a '#' inside of it, it means that it is
probably followed up with a comment such as license for that package and
it will fail to install because pip will try to use that literal #.

Change-Id: I31c5ffe3dda3ced4b6a412cc955c73321d4af507

docker/python-builder/scripts/get-extras-packages

@@ -28,6 +28,8 @@ def get_extras_packages(path):
     for name, packages in config.items():
         for package in packages.split('\n'):
             package = package.strip()
+            if '#' in package:
+                package = package.split('#')[0]
             if not package:
                 continue
             extras.add(package)