stash: simplify parsing fixes

This patch simplifies Brian's fix for the recent regression by:

* eliminating the extra loop
* eliminating use of git rev-parse for parsing flags
* making use of the for opt idiom for the retained loop
* eliminating the redundant -- case

The patch has been tested with the tests in current maint.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-stash.sh

@@ -264,36 +264,22 @@ parse_flags_and_rev()
 	b_tree=
 	i_tree=
 
-	# Work around rev-parse --flags eating -q
-	for opt
-	do
-		case "$opt" in
-		-q|--quiet)
-			GIT_QUIET=t
-			;;
-		esac
-	done
-
 	REV=$(git rev-parse --no-flags --symbolic "$@" 2>/dev/null)
-	FLAGS=$(git rev-parse --no-revs --flags "$@" 2>/dev/null)
-
-	set -- $FLAGS
 
 	FLAGS=
-	while test $# -ne 0
+	for opt
 	do
-		case "$1" in
+		case "$opt" in
+			-q|--quiet)
+				GIT_QUIET=-t
+			;;
 			--index)
 				INDEX_OPTION=--index
 			;;
-			--)
-				:
-			;;
-			*)
-				FLAGS="${FLAGS}${FLAGS:+ }$1"
+			-*)
+				FLAGS="${FLAGS}${FLAGS:+ }$opt"
 			;;
 		esac
-		shift
 	done
 
 	set -- $REV