[RFE] git rebase doesn't say it failed

Hello!

What happened:
  I tried to do a rebase and got a message about files "needs  
update".  However, it didn't say it did a rebase nor did it say that  
it failed.
Example:
+ git rebase origin/master
f1: needs update

What I expected:
  It should have said that it was unable to rebase because of these  
files.
Example:
+ git rebase origin/master
f1: needs update
Git was unable to rebase due to the files above.  Please commit them  
or move them out of the way.
Hint: See "git reset --help" for a suggestion about saving work in  
progress.

Notes: I have had several users at the company that I work think that these messages meant that it worked fine. There are some commands (like reset, co, etc.) that show these kind of messages and it isn't an error; they were conditioned to think they were acceptable messages.

version: 1.5.4.3

Shell script to recreate the problem: #!/bin/sh

set -eux

rm -rf a b mkdir a cd a git init echo 1 > f1 echo 1 > f2 git add f? git commit -m "init"

cd .. git clone a b

cd b echo 1.5 > f1

cd ../a echo 2 > f2 git commit -m "2" f2

cd ../b git fetch git rebase origin/master

#EOF