Merge pull request DSpace#2021 from atmire/default-configuration-fix

"default" search configuration fix

Author: tdonohue

src/app/shared/search/search.component.ts

@@ -67,7 +67,7 @@ export class SearchComponent implements OnInit {
    * The configuration to use for the search options
    * If empty, 'default' is used
    */
-  @Input() configuration = 'default';
+  @Input() configuration;
 
   /**
    * The actual query for the fixed filter.