get_form_option fixup

python/dune/perftool/pdelab/driver/vtk.py

 from dune.perftool.generation import (include_file,
                                       preamble,
                                       )
-from dune.perftool.options import (get_form_option,
-                                   get_option,
-                                   )
+from dune.perftool.options import get_form_option
 from dune.perftool.pdelab.driver import (get_form_ident,
                                          get_trial_element,
                                          name_initree,
@@ -48,7 +46,7 @@ def define_subsamplinglevel(name):
     if isinstance(degree, tuple):
         degree = max(degree)
     if get_form_option("blockstructured"):
-        degree *= get_option("number_of_blocks")
+        degree *= get_form_option("number_of_blocks")
     return "Dune::RefinementIntervals {}({}.get<int>(\"vtk.subsamplinglevel\", {}));".format(name, ini, max(degree, 1))