fixed typo in 4d oo routine.

Author: jacobwilliams

src/bspline_oo_module.f90

@@ -341,7 +341,7 @@ subroutine initialize_4d(me,x,y,z,q,fcn,kx,ky,kz,kq,iflag)
     nx = size(x)
     ny = size(y)
     nz = size(z)
-    nq = size(z)
+    nq = size(q)
 
     me%nx = nx
     me%ny = ny