rebase: align variable content

Make sure to interpret variables with the same name in the same way in
git-rebase.sh and git-rebase--interactive.sh. This will make it easier
to factor out code from git-rebase.sh to git-rebase--interactive and
export the variables.

Signed-off-by: Martin von Zweigbergk <martin.von.zweigbergk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-rebase--interactive.sh

@@ -339,7 +339,8 @@ pick_one_preserving_merges () {
 			# No point in merging the first parent, that's HEAD
 			new_parents=${new_parents# $first_parent}
 			if ! do_with_author output \
-				git merge $strategy -m "$msg_content" $new_parents
+				git merge ${strategy:+-s $strategy} -m \
+					"$msg_content" $new_parents
 			then
 				printf "%s\n" "$msg_content" > "$GIT_DIR"/MERGE_MSG
 				die_with_patch $sha1 "Error redoing merge $sha1"
@@ -827,11 +828,11 @@ first and then run 'git rebase --continue' again."
 	-s)
 		case "$#,$1" in
 		*,*=*)
-			strategy="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
+			strategy=$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
 		1,*)
 			usage ;;
 		*)
-			strategy="-s $2"
+			strategy="$2"
 			shift ;;
 		esac
 		;;
@@ -860,9 +861,9 @@ first and then run 'git rebase --continue' again."
 		autosquash=
 		;;
 	--onto)
+		test 2 -le "$#" || usage
+		onto="$2"
 		shift
-		onto=$(parse_onto "$1") ||
-			die "Does not point to a valid commit: $1"
 		;;
 	--)
 		shift
@@ -872,6 +873,11 @@ first and then run 'git rebase --continue' again."
 	shift
 done
 
+if test -n "$onto"
+then
+	onto=$(parse_onto "$onto") || die "Does not point to a valid commit: $1"
+fi
+
 test -z "$rebase_root" -a $# -ge 1 -a $# -le 2 ||
 test ! -z "$rebase_root" -a $# -le 1 || usage
 test -d "$dotest" &&

git-rebase.sh

@@ -43,7 +43,7 @@ If you would prefer to skip this patch, instead run \"git rebase --skip\".
 To restore the original branch and stop rebasing run \"git rebase --abort\".
 "
 unset onto
-strategy=recursive
+strategy=
 strategy_opts=
 do_merge=
 merge_dir="$GIT_DIR"/rebase-merge
@@ -130,6 +130,7 @@ call_merge () {
 	then
 		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
 	fi
+	test -z "$strategy" && strategy=recursive
 	eval 'git-merge-$strategy' $strategy_opts '"$cmt^" -- "$hd" "$cmt"'
 	rv=$?
 	case "$rv" in
@@ -267,6 +268,7 @@ do
 		esac
 		strategy_opts="$strategy_opts $(git rev-parse --sq-quote "--$newopt")"
 		do_merge=t
+		test -z "$strategy" && strategy=recursive
 		;;
 	-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 		--strateg=*|--strategy=*|\