By Patrick Gower, Bloomberg News Spinal Tap is regrouping to demand that Vivendi, the distributor of the 1984 cult film, give them some money. Christopher Guest, Michael McKean and Rob Reiner — who played singer Nigel Tufnel, lead guitarist David St. Hubbins and director Marty Di Bergi in “This is Spinal Tap” — joined bass player Harry Shearer’s lawsuit against Vivendi.