Bug 29843: Use in opac/opac-privacy.pl

Bug 29843: Use in opac/opac-privacy.pl

This patch makes the opac/opac-privacy.pl OPAC page use the new
anonymize method.

To test:
1. Have some checked-in materiales
2. Have OPACPrivacy enabled
3. Notice your checkouts history contains what you expect
4. Go to 'your privacy'
5. Click on 'Delete checkout history'
=> SUCCESS: It works, no crash.
6. Sign off :-D

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>