gnu: python-markupsafe: Do not set PYTHONPATH.

* gnu/packages/python-xyz.scm (python-markupsafe)
[phases]{check}: Do not set PYTHONPATH.

gnu/packages/python-xyz.scm

@@ -3178,21 +3178,10 @@ (define-public python-markupsafe
          "0sqipg4fk7xbixqd8kq6rlkxj664d157bdwbh93farcphf92x1r9"))))
     (build-system python-build-system)
     (arguments
-     `(#:modules ((ice-9 ftw)
-                  (srfi srfi-1)
-                  (srfi srfi-26)
-                  (guix build utils)
-                  (guix build python-build-system))
-       #:phases (modify-phases %standard-phases
+     `(#:phases (modify-phases %standard-phases
                   (replace 'check
                     (lambda _
-                      (let ((cwd (getcwd))
-                            (libdir (find (cut string-prefix? "lib." <>)
-                                          (scandir "build"))))
-                      (setenv "PYTHONPATH"
-                              (string-append cwd "/build/" libdir ":"
-                                             (getenv "PYTHONPATH")))
-                      (invoke "pytest" "-vv")))))))
+                      (invoke "pytest" "-vv"))))))
     (native-inputs
      `(("python-pytest" ,python-pytest)))
     (home-page "https://github.com/mitsuhiko/markupsafe")