Bug 34979: (follow-up) Only print message when preference was added

Bug 34979: (follow-up) Only print message when preference was added

Implements Joubu's suggestion from comment#14 and improves
on it for the cases where we fix capitalization.

Test plan remains unchanged. You can run the database update
a second time to see the difference.

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 92d98c1808f4ae12a91263a8c68099753259084a)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>