python314Packages.ray: fix the eval

Without the change the eval fails in an obscure way
by trying to evaluate set as a string:

    $ nix build -f. python314Packages.ray.src
    error:
       … while calling a functor (an attribute set with a '__functor' attribute)
         at pkgs/development/python-modules/ray/default.nix:116:5:
          115|     in
          116|     fetchPypi {
             |     ^
          117|       inherit pname version format;

       … while evaluating a branch condition
         at lib/customisation.nix:199:7:
          198|       in
          199|       if isAttrs result then
             |       ^
          200|         result

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: cannot coerce a set to a string: { }

After the change the failure is reported via catchable `throw`:

    $ nix build -f. python314Packages.ray.src
    error:
       … while calling a functor (an attribute set with a '__functor' attribute)
         at pkgs/development/python-modules/ray/default.nix:116:5:
          115|     in
          116|     fetchPypi {
             |     ^
          117|       inherit pname version format;

       … while evaluating a branch condition
         at lib/customisation.nix:199:7:
          198|       in
          199|       if isAttrs result then
             |       ^
          200|         result

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: No hash specified for 'x86_64-linux.cp314'

0 files changed, 0 insertions, 0 deletions