I find pylint useful, but I also find it is horrifically undocumented, has painfully verbose output, and lacks an intuitive interface.
pylint
If I'm not mistaken, you should be able to use --disable-msg-cat=C (can't remember whether it's uppercase or lowercase or both) to accomplish this.
--disable-msg-cat=C
UPDATE: In later versions of pylint, you should use --disable=C
--disable=C