diffgout doesn't work in user installation

[alexsavulescu]

 diffgout 147514/dendritic_complexity/gout 147514-nightly/dendritic_complexity/gout
(venv-nightly) savulesc@bbd-cjngk03:~/Workspace/nrn/build$ /home/savulesc/Workspace/nrn/venv-nightly/bin/nrngui:11: DeprecationWarning: The distutils package is deprecated and slated for removal in Python 3.12. Use setuptools or check PEP 632 for potential alternatives
  from distutils.ccompiler import new_compiler
INFO : Using neuron-nightly Package (Developer Version)
NEURON -- VERSION 9.0.dev-98-g3e0e1eb4 HEAD (3e0e1eb4) 2022-10-17
Duke, Yale, and the BlueBrain Project -- Copyright 1984-2022
See http://neuron.yale.edu/neuron/credits

0 /home/savulesc/Workspace/nrn/venv-nightly/lib/python3.10/site-packages/neuron/.data/bin/nrniv: can't open modeldb/showgout.hoc

we need to use the proper path for showgout.hoc