Revert parts of "gnu: Add i7z."

This reverts parts of commit a8b705252bdcb642999258859ada1c2f43706092,
because it's apparently revert things day, and also I'm an idiot

gnu/packages/radio.scm

@@ -481,13 +481,11 @@ used by RDS Spy, and audio files containing @dfn{multiplex} signals (MPX).")
     (version "3.9.0.0")
     (source
      (origin
-       (method git-fetch)
-       (uri (git-reference
-             (url "https://github.com/gnuradio/gnuradio")
-             (commit (string-append "v" version))))
-       (file-name (git-file-name name version))
+       (method url-fetch)
+       (uri (string-append "https://www.gnuradio.org/releases/gnuradio/"
+                           "gnuradio-" version ".tar.xz"))
        (sha256
-        (base32 "1fbl8lslzrkx7lpkibhvs6gvhqnn8yrrq3n6irybfnifh2536d36"))))
+        (base32 "1jvm9xd0l2pz1fww4zii6hl7ccnvy256nrf70ljb594n7j9j49ha"))))
     (build-system cmake-build-system)
     (native-inputs
      `(("doxygen" ,doxygen)
@@ -552,11 +550,6 @@ used by RDS Spy, and audio files containing @dfn{multiplex} signals (MPX).")
                             "/share/javascript/mathjax"))
        #:phases
        (modify-phases %standard-phases
-         (add-after 'unpack 'make-source-writable
-           (lambda _
-             ;; The test_add and test_newmod open(sources, "w") for some reason.
-             (for-each make-file-writable
-                       (find-files "." ".*"))))
          (add-after 'unpack 'fix-paths
            (lambda* (#:key inputs #:allow-other-keys)
              (let ((qwt (assoc-ref inputs "qwt")))

gnu/packages/shells.scm

@@ -945,7 +945,7 @@ files and text.")
 (define-public nushell
   (package
     (name "nushell")
-    (version "0.33.0")
+    (version "0.32.0")
     (source
      (origin
        (method git-fetch)
@@ -954,7 +954,7 @@ files and text.")
              (commit version)))
        (file-name (git-file-name name version))
        (sha256
-        (base32 "0rdvvg6hf01bljq0zz0c66kbzy5ggbcbil1j45hklzq0ibffdj02"))))
+        (base32 "1wj054rzv88ys4ask4zp7crrw0dxrck8svlj3i16qqd8x5dnyhqs"))))
     (build-system cargo-build-system)
     (arguments
      `(#:rust ,rust-1.47
@@ -995,7 +995,6 @@ files and text.")
         ("rust-nu-plugin-to-sqlite" ,rust-nu-plugin-to-sqlite-0.32)
         ("rust-nu-plugin-tree" ,rust-nu-plugin-tree-0.32)
         ("rust-nu-plugin-xpath" ,rust-nu-plugin-xpath-0.32)
-        ("rust-polars-0.13" ,rust-polars-0.13)
         ("rust-pretty-env-logger" ,rust-pretty-env-logger-0.4))
        #:cargo-development-inputs
        (("rust-dunce" ,rust-dunce-1)