build-dotnet-module/fetch-deps: fixup temp naming when pname has a capital X in it

For example, this script doesn't work for `xivlauncher` because its
proper `pname` is `XIVLauncher`, and `mktemp` complains about "too few
X's":

    $ mktemp -td "XXXXXX-XIVLauncher-home"
    mktemp: too few X's in template ‘XXXXXX-XIVLauncher-home’

vs

    $ mktemp -td "XIVLauncher-home-XXXXXX"
    /tmp/XIVLauncher-home-EdGMei

pkgs/build-support/dotnet/build-dotnet-module/default.nix

@@ -180,12 +180,12 @@ in stdenvNoCC.mkDerivation (args // {
               ;;
       esac
 
-      deps_file="$(realpath "''${1:-$(mktemp -t "XXXXXX-${pname}-deps.nix")}")"
-      export HOME=$(mktemp -td "XXXXXX-${pname}-home")
+      deps_file="$(realpath "''${1:-$(mktemp -t "${pname}-deps-XXXXXX.nix")}")"
+      export HOME=$(mktemp -td "${pname}-home-XXXXXX")
       mkdir -p "$HOME/nuget_pkgs"
 
       store_src="${srcOnly args}"
-      src="$(mktemp -td "XXXXXX-${pname}-src")"
+      src="$(mktemp -td "${pname}-src-XXXXXX")"
       cp -rT "$store_src" "$src"
       chmod -R +w "$src"
       trap "rm -rf $src $HOME" EXIT