Remove execution permission from setup-env.sh (#45641)

`setup-env.sh` is meant to be sourced, not executed directly.
By revoking execution permissions, users who accidentally execute
the script will receive an error instead of seeing no effect.

* Remove execution permission from `setup-env.sh` and friends
* Don't make output file executable in `spack commands --update-completion`

---------

Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>
Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>

lib/spack/spack/cmd/commands.py

@@ -11,7 +11,6 @@
 from argparse import ArgumentParser, Namespace
 from typing import IO, Any, Callable, Dict, Iterable, List, Optional, Sequence, Set, Tuple, Union
 
-import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.argparsewriter import ArgparseRstWriter, ArgparseWriter, Command
 from llnl.util.tty.colify import colify
@@ -867,9 +866,6 @@ def _commands(parser: ArgumentParser, args: Namespace) -> None:
             prepend_header(args, f)
             formatter(args, f)
 
-        if args.update_completion:
-            fs.set_executable(args.update)
-
     else:
         prepend_header(args, sys.stdout)
         formatter(args, sys.stdout)