I don't think his buyout is even close to high enough to deter Texas. I wouldn't read into this too much. A couple tweets from a coaching website:
FootballScoop Staff @footballscoop 4h
Unless there is a shocking buyout figure in there (which I doubt given leverage) this new contract for Fisher means very little re: Texas
FootballScoop Staff @footballscoop 3h
Jimbo, Briles, Saban all earned new deals, UT being / coming open just provided more leverage. None of those however lock UT out.