Travis: Fix installation of package wheel.
Travis: Fix installation of package wheel.

msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,retuxx/tinyspline,retuxx/tinyspline,msteinbeck/tinyspline,retuxx/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline