Jennie Garth says starring in ‘Beverly Hills, 90210′ was “worse than high school”.The blonde beauty - who reprises her role as Kelly Taylor in a new spin-off of the hit US TV show - admits the rivalry on set was almost unbearable.She said: “There were times when being in the show was worse than high school. The environment there was like, ‘Are you kidding me?’ There was a lot of tension and unnecessary drama on the set, a certain amount of competition, and a certain, probably, anger about different salaries as the years progressed.”People would find out how much someone was making, and then they’d be angry and want that, or if you got days off in your contract, they’d want that. Nobody was brave enough to step in and set us straight, and have a serious talk with us about it. There was a lot of tension directed from…