completion: use ls -1 instead of rolling a loop to do that ourselves

This simplifies the code a great deal.  In particular, it allows us to
get rid of __git_shopt, which is used only in this fuction to enable
'nullglob' in zsh.

[jn: squashed with a patch that actually gets rid of __git_shopt]

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -643,13 +643,8 @@ __git_refs_remotes ()
 
 __git_remotes ()
 {
-	local i ngoff IFS=$'\n' d="$(__gitdir)"
-	__git_shopt -q nullglob || ngoff=1
-	__git_shopt -s nullglob
-	for i in "$d/remotes"/*; do
-		echo ${i#$d/remotes/}
-	done
-	[ "$ngoff" ] && __git_shopt -u nullglob
+	local i IFS=$'\n' d="$(__gitdir)"
+	test -d "$d/remotes" && ls -1 "$d/remotes"
 	for i in $(git --git-dir="$d" config --get-regexp 'remote\..*\.url' 2>/dev/null); do
 		i="${i#remote.}"
 		echo "${i/.url*/}"
@@ -2736,33 +2731,3 @@ if [ Cygwin = "$(uname -o 2>/dev/null)" ]; then
 complete -o bashdefault -o default -o nospace -F _git git.exe 2>/dev/null \
 	|| complete -o default -o nospace -F _git git.exe
 fi
-
-if [[ -n ${ZSH_VERSION-} ]]; then
-	__git_shopt () {
-		local option
-		if [ $# -ne 2 ]; then
-			echo "USAGE: $0 (-q|-s|-u) <option>" >&2
-			return 1
-		fi
-		case "$2" in
-		nullglob)
-			option="$2"
-			;;
-		*)
-			echo "$0: invalid option: $2" >&2
-			return 1
-		esac
-		case "$1" in
-		-q)	setopt | grep -q "$option" ;;
-		-u)	unsetopt "$option" ;;
-		-s)	setopt "$option" ;;
-		*)
-			echo "$0: invalid flag: $1" >&2
-			return 1
-		esac
-	}
-else
-	__git_shopt () {
-		shopt "$@"
-	}
-fi