Revert "gplates: fix failing build"

This reverts commit 8a236e246a.

pkgs/applications/science/misc/gplates/default.nix

@@ -14,15 +14,13 @@
 , libGLU
 , mpfr
 , proj
-# build with Python 3.10 fails, because boost <= 1.78 can't find
-# pythons with double digits in minor versions, like X.YZ
-, python39
+, python3
 , qtxmlpatterns
 , qwt
 }:
 
 let
-  python = python39.withPackages (ps: with ps; [
+  python = python3.withPackages (ps: with ps; [
     numpy
   ]);
   boost' = boost.override {

pkgs/top-level/all-packages.nix

@@ -36228,6 +36228,8 @@ with pkgs;
 
   gplates = libsForQt5.callPackage ../applications/science/misc/gplates {
     boost = boost175;
+    # build with Python 3.10 fails, because boost <= 1.78 can't find
+    # pythons with double digits in minor versions, like X.YZ
     python3 = python39;
   };