Organic Groups colors mismatch

The code that generates the CSS-file for OG colors creates selectors for class names like "colors-og-1", "colors-og-2" etc.

The code that generates the actual classes on the elements generates classes like "colors-og1", "colors-og2" etc. so the CSS rules are not applied.

I don't uderstand the color module's code (there's so much going on implicitly and "magically" via ctools), and I couldn't find the place where the names are generated, but I think I found the code that generates the classes to be used in the element. For some obscure reason the names are generated with underscores instead of dashes, but in the output the classes come out with dashes. However, this patch seems to work.