Use comments rather than no-op string statements

This change replaces a few no-op string statements with regular
comments.  While there was no harm in the previous use of strings for
comments, this allows us to re-enable the corresponding pylint check
which may catch genuinely unintended cases.

Change-Id: I796a059292e26c4df75c54f095d9e20e99187c98
Merge "Use comments rather than no-op string statements"