As suggested by Nicole, when a library hides the names of the
reviewers, they probably don't want to show their faces.
The OPAC detail page was already hiding these avatars but this
change also prevents Koha from looking for these avatars (which
could incur DNS queries) if they're not going to be displayed.
Signed-off-by: Francois Marier <francois@debian.org> Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com> Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>