Call reindent() until no further changes occur

Six files in the VTK source required vtk_reindent_code.py to be called twice in order for the indentation to be corrected (all other files only required it to be called once). The problem with those six files was nested blocks where all source lines between the beginning of the outer block and the beginning of the inner block were comments. There is probably a way to fix the script so that it properly deals with this situation, but simply re-processing the file until no further changes occur is a robust solution that gives the correct result.