harmless changes to quiet clang static check warnings.

- made EXPANDED_AGRP take bAnimContext as an argument.
- remove unneeded NULL check drawFacesColored functions.
- comment some vars which are set but not used.

source/blender/editors/space_node/drawnode.c

@@ -1643,6 +1643,8 @@ void draw_nodespace_color_info(ARegion *ar, int color_manage, int channels, int
 		BLF_draw_ascii(blf_mono_font, str, sizeof(str));
 		dx += BLF_width(blf_mono_font, str);
 	}
+
+	(void)dx;
 }
 
 #if 0