Fix the print of the rebase error message, and make the output prettier too.

For some reason .output doesn't throw an AttributeError, but returns None ,
instead. .stdout is the correct attribute.

R=agable@chromium.org
BUG=

Review URL: https://codereview.chromium.org/212493003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@259695 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/git_rebase_update.py b/git_rebase_update.py
index 9d353c6..37f3066 100755
--- a/git_rebase_update.py
+++ b/git_rebase_update.py
@@ -137,6 +137,9 @@
       else:
         # rebase and leave in mid-rebase state.
         git.rebase(parent, start_hash, branch)
+        print "Failed!"
+        print
+        print "Here's what git-rebase had to say:"
         print squash_ret.message
         print
         print textwrap.dedent(