Use cd_to_toplevel in scripts that implement it by hand.

This converts scripts that do "cd $(rev-parse --show-cdup)" by
hand to use cd_to_toplevel.

I think git-fetch does not have to go to the toplevel, but that
should be dealt with in a separate patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git-checkout.sh

@@ -135,11 +135,7 @@ fi
 
 # We are switching branches and checking out trees, so
 # we *NEED* to be at the toplevel.
-cdup=$(git-rev-parse --show-cdup)
-if test ! -z "$cdup"
-then
-	cd "$cdup"
-fi
+cd_to_toplevel
 
 [ -z "$new" ] && new=$old && new_name="$old_name"
 

git-commit.sh

@@ -316,22 +316,16 @@ esac
 ################################################################
 # Prepare index to have a tree to be committed
 
-TOP=`git-rev-parse --show-cdup`
-if test -z "$TOP"
-then
-	TOP=./
-fi
-
 case "$all,$also" in
 t,)
 	save_index &&
 	(
-		cd "$TOP"
-		GIT_INDEX_FILE="$NEXT_INDEX"
-		export GIT_INDEX_FILE
+		cd_to_toplevel &&
+		GIT_INDEX_FILE="$NEXT_INDEX" &&
+		export GIT_INDEX_FILE &&
 		git-diff-files --name-only -z |
 		git-update-index --remove -z --stdin
-	)
+	) || exit
 	;;
 ,t)
 	save_index &&
@@ -339,11 +333,11 @@ t,)
 
 	git-diff-files --name-only -z -- "$@"  |
 	(
-		cd "$TOP"
-		GIT_INDEX_FILE="$NEXT_INDEX"
-		export GIT_INDEX_FILE
+		cd_to_toplevel &&
+		GIT_INDEX_FILE="$NEXT_INDEX" &&
+		export GIT_INDEX_FILE &&
 		git-update-index --remove -z --stdin
-	)
+	) || exit
 	;;
 ,)
 	case "$#" in

git-fetch.sh

@@ -5,12 +5,8 @@ USAGE='<fetch-options> <repository> <refspec>...'
 SUBDIRECTORY_OK=Yes
 . git-sh-setup
 set_reflog_action "fetch $*"
+cd_to_toplevel ;# probably unnecessary...
 
-TOP=$(git-rev-parse --show-cdup)
-if test ! -z "$TOP"
-then
-	cd "$TOP"
-fi
 . git-parse-remote
 _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"

git-reset.sh

@@ -53,11 +53,7 @@ then
 	exit
 fi
 
-TOP=$(git-rev-parse --show-cdup)
-if test ! -z "$TOP"
-then
-	cd "$TOP"
-fi
+cd_to_toplevel
 
 if test "$reset_type" = "--hard"
 then