Don't "double" cache a facet filter / query facet, closes elastic#734.

Author: kimchy

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/filter/FilterFacetCollector.java

@@ -42,7 +42,7 @@ public class FilterFacetCollector extends AbstractFacetCollector {
 
     public FilterFacetCollector(String facetName, Filter filter, FilterCache filterCache) {
         super(facetName);
-        this.filter = filterCache.cache(filter);
+        this.filter = filter;
     }
 
     @Override protected void doSetNextReader(IndexReader reader, int docBase) throws IOException {

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/query/QueryFacetCollector.java

@@ -48,9 +48,9 @@ public QueryFacetCollector(String facetName, Query query, FilterCache filterCach
         super(facetName);
         Filter possibleFilter = extractFilterIfApplicable(query);
         if (possibleFilter != null) {
-            this.filter = filterCache.cache(possibleFilter);
+            this.filter = possibleFilter;
         } else {
-            this.filter = filterCache.cache(new QueryWrapperFilter(query));
+            this.filter = new QueryWrapperFilter(query);
         }
     }