title: Django admin do not show search term in changelist url
body: <p>I have modified the <a href="https://docs.djangoproject.com/en/1.8/ref/contrib/admin/#django.contrib.admin.ModelAdmin.get_search_results" rel="nofollow">get_search_results</a> method of django admin changelist to use custom search method. I am using large text string as input to the search, so I don't want the search term to appear in the url. How can I remove the search term from the changelist url ?</p>
  
  <pre><code>def get_search_results(self, request, queryset, search_term):
      """
      Returns a tuple containing a queryset to implement the search,
      and a boolean indicating if the results may contain duplicates.
      """
      # Apply keyword searches.
      def construct_search(field_name):
          if field_name.startswith('^'):
              return "%s__istartswith" % field_name[1:]
          elif field_name.startswith('='):
              return "%s__iexact" % field_name[1:]
          elif field_name.startswith('@'):
              return "%s__search" % field_name[1:]
          else:
              return "%s__icontains" % field_name
  
      use_distinct = False
      if search_term:
          # here input is large text string
          sites = get_sites_from_text(search_term)
          search_fields = self.get_search_fields(request)
          if len(sites) &gt; 0:
              queryset = queryset.filter(site_name__in=sites)
          elif search_fields:
              orm_lookups = [construct_search(str(search_field))
                             for search_field in search_fields]
              for bit in search_term.split():
                  or_queries = [models.Q(**{orm_lookup: bit})
                                for orm_lookup in orm_lookups]
                  queryset = queryset.filter(
                      reduce(operator.or_, or_queries))
              if not use_distinct:
                  for search_spec in orm_lookups:
                      if lookup_needs_distinct(self.opts, search_spec):
                          use_distinct = True
                          break
  
      return queryset, use_distinct
  </code></pre>