I think the Rams COULD still take a CB early if they want, this signing just means they don't HAVE to do so.
The moves the Rams have made have been really solid in and of themselves, but the best part is how much they have opened up their draft options.
We have gone from absolutely needing to draft a WR early (nope - resign Demarcus) to having to draft OL early (nope - resign Dotson, add Jonah Jackson and tender AJax) to having to draft a TE to replace Higbee (nope - add Parkinson), to really needing to draft a DB early (nope, add DWill, Curl and TWhite).
They still could draft any one of those early, but they don't HAVE to do so.
Now, they haven't done that with the DLine (yet?), so currently, they HAVE to draft Edge and DT (and probably DE), but other than that, they have been able to remove a lot of the NO CHOICE BUT TO DRAFT X position.