rebase: Make the fast-fowarding message more user-friendly by using branch names instead of SHA1 IDs.

Signed-off-by: Robert Shearman <rob@codeweavers.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-rebase.sh

@@ -280,7 +280,7 @@ git-reset --hard "$onto"
 # we just fast forwarded.
 if test "$mb" = "$branch"
 then
-	echo >&2 "Fast-forwarded $branch to $newbase."
+	echo >&2 "Fast-forwarded $branch_name to $onto_name."
 	exit 0
 fi