rebase: distinguish user input by quoting it

Signed-off-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-rebase.sh

@@ -477,7 +477,7 @@ then
 		;;
 	esac
 	upstream=$(peel_committish "${upstream_name}") ||
-	die "$(eval_gettext "invalid upstream \$upstream_name")"
+	die "$(eval_gettext "invalid upstream '\$upstream_name'")"
 	upstream_arg="$upstream_name"
 else
 	if test -z "$onto"
@@ -539,7 +539,7 @@ case "$#" in
 		head_name="detached HEAD"
 
 	else
-		die "$(eval_gettext "fatal: no such branch/commit: \$branch_name")"
+		die "$(eval_gettext "fatal: no such branch/commit '\$branch_name'")"
 	fi
 	;;
 0)