500 error on`/search/?query=<value>`

[sbesson]

Can be reproduced on prod114 and/or test114 with the following stack trace

Traceback (most recent call last):
  File "/opt/omero/web/venv3/lib64/python3.6/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/opt/omero/web/venv3/lib64/python3.6/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/omero/web/venv3/lib64/python3.6/site-packages/omeroweb/decorators.py", line 538, in wrapped
    retval = f(request, *args, **kwargs)
  File "/opt/omero/web/venv3/lib64/python3.6/site-packages/omeroweb/decorators.py", line 597, in wrapper
    context = f(request, *args, **kwargs)
  File "/opt/omero/web/venv3/lib64/python3.6/site-packages/idr_gallery/views.py", line 75, in index
    value=keyval[1],
IndexError: list index out of range

[will-moore]

Fixed by #27