gnu: Fix merge mistakes.

* gnu/packages/chez.scm (chez-scheme)[native-inputs]: Use correct
texlive implementation.
* gnu/packages/music.scm (python-abjad)[native-inputs],
* gnu/packages/python-check.scm (python-pytest-helpers-namespace)
[native-inputs]: Use correct variable for python-pytest.

gnu/packages/chez.scm

@@ -114,8 +114,8 @@
        ;; for docs
        ("stex" ,stex)
        ("xorg-rgb" ,xorg-rgb)
-       ("texlive" ,(texlive-union (list texlive-latex-oberdiek
-                                        texlive-generic-epsf)))
+       ("texlive" ,(texlive-updmap.cfg (list texlive-latex-oberdiek
+                                             texlive-generic-epsf)))
        ("ghostscript" ,ghostscript)
        ("netpbm" ,netpbm)))
     (native-search-paths

gnu/packages/music.scm

@@ -1530,7 +1530,7 @@ Guile.")
        ("python-isort" ,python-isort)
        ("python-mypy" ,python-mypy)
        ("python-ply" ,python-ply)
-       ("python-pytest" ,python-pytest-6)
+       ("python-pytest" ,python-pytest)
        ("python-pytest-cov" ,python-pytest-cov)
        ("python-sphinx-autodoc-typehints" ,python-sphinx-autodoc-typehints)))
     (propagated-inputs

gnu/packages/python-check.scm

@@ -396,7 +396,7 @@ sub-package.")
              (add-installed-pythonpath inputs outputs)
              (invoke "pytest" "-vv"))))))
     (native-inputs
-     `(("python-pytest" ,python-pytest-6)
+     `(("python-pytest" ,python-pytest)
        ("python-setuptools" ,python-setuptools) ; needs setuptools >= 50.3.2
        ("python-setuptools-scm" ,python-setuptools-scm)
        ("python-setuptools-declarative-requirements"