BUG: [Cosmetic] Commiting a gerrit ChangeId before the commit hook was installed

I was trying to send a new version of a patch to a gerrit server from a new computer, so I made a change with a ChangeId in the description and tried to review it:

strainu@emily:~/core> git branch archivebot
strainu@emily:~/core> git checkout archivebot
M       pywikibot/page.py
Switched to branch 'archivebot'
strainu@emily:~/core> git diff
strainu@emily:~/core> git add .
strainu@emily:~/core> git commit
[archivebot 282ad24] Update getFileVersionHistoryTable.
 1 file changed, 3 insertions(+), 4 deletions(-)
strainu@emily:~/core> git review -f
Creating a git remote called "gerrit" that maps to:
        ssh://strainu@gerrit.wikimedia.org:29418/pywikibot/core.git
Your change was committed before the commit hook was installed.
Amending the commit to add a gerrit change id.

At this point I ended the transaction, as I was confused by the last message: I was afraid the ChangeId would have changed, causing the patch to be attached to another review.

I think git should not show this message if the change description already has a change id, or at least add another message that clarifies the fact that the change id has not changed.

Thanks,
   Strainu