Bug 11159: fix small typo in catalogue/results.tt

Bug 11159: fix small typo in catalogue/results.tt

In catalogue/results.tt, there is a small HTML error line 377 :
[% ELSE %]<option value"au,phr">Author</option>[% END %]
The = is missing

Test plan :
- In intranet, test go to advanced search
- Click on [More options]
- Enter a term, check "Scan indexes" and click on "Search"
- Look at HTML code of select "Indexed in"
=> option "Author" is correct : <option value="au,phr">Author</option>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>