classifier: Drop CLS_INC_* enumerations and related 'include' parameters.

classifier: Drop CLS_INC_* enumerations and related 'include' parameters.

This type and these parameters were useful when ofproto had the need to
separately traverse exact-match rules looking for subrules, but it no
longer does that because subrules (now called "facets") are not kept in
the classifier any longer.  All the callers are now passing CLS_INC_ALL
anyhow, so we might as well delete this feature and simplify the code.