This is a follow-up to commit 18ab54d4a2
and fixes a regression introduced by Nyx 2.0.4 + Python 3.
* gnu/packages/tor.scm (nyx)[source]: Add patch.
* gnu/packages/patches/nyx-show-header-stats-with-python3.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.