Write just ./.version on all components

This way it's easier to get right. See previous commit.

src/libutil-tests/package.nix

@@ -45,14 +45,6 @@ mkMesonExecutable (finalAttrs: {
     gtest
   ];
 
-  preConfigure =
-    # "Inline" .version so it's not a symlink, and includes the suffix.
-    # Do the meson utils, without modification.
-    ''
-      chmod u+w ./.version
-      echo ${version} > ../../.version
-    '';
-
   mesonFlags = [
   ];