Firefox mediaConstraints update

Hello,

I see just now the licode update for Firefox with new mediaConstraints for
peerConnection:

https://github.com/ging/licode/commit/e2d833523ce174b2f2e3986d4d68b956b47e7987

I suppose that it came to solve this Firefox bug:

https://bugzilla.mozilla.org/show_bug.cgi?id=1063808

But I thing this is an update only for Firefox +32 so, after this update,
when we create a SDP in Firefox 31 or less it could have a wrong behavior,
doesn’t?

I think we need build some If-else estament for select the correct
mediaConstraints format.

Best regards,

Toni Paricio.