Revert "git stash: avoid data loss when "git stash save" kills a directory"

This reverts commit a73653130e, as it
has been reported that "ls-files --killed" is too time-consuming in
a deep directory with too many untracked crufts (e.g. $HOME/.git
tracking only a few files).

We'd need to revisit it later but "ls-files --killed" needs to be
optimized before it happens.

git-stash.sh

@@ -195,7 +195,6 @@ save_stash () {
 	keep_index=
 	patch_mode=
 	untracked=
-	force=
 	while test $# != 0
 	do
 		case "$1" in
@@ -216,9 +215,6 @@ save_stash () {
 		-u|--include-untracked)
 			untracked=untracked
 			;;
-		-f|--force)
-			force=t
-			;;
 		-a|--all)
 			untracked=all
 			;;
@@ -262,14 +258,6 @@ save_stash () {
 		say "$(gettext "No local changes to save")"
 		exit 0
 	fi
-	if test -z "$untracked$force" &&
-	   test -n "$(git ls-files --killed | head -n 1)"
-	then
-		say "$(gettext "The following untracked files would NOT be saved but need to be removed by stash save:")"
-		test -n "$GIT_QUIET" || git ls-files --killed | sed 's/^/\t/'
-		say "$(gettext "Aborting. Consider using either the --force or --include-untracked option.")" >&2
-		exit 1
-	fi
 	test -f "$GIT_DIR/logs/$ref_stash" ||
 		clear_stash || die "$(gettext "Cannot initialize stash")"