fix fascets merge

Author: moshaad7

search/facets_builder.go

@@ -321,7 +321,11 @@ func (fr *FacetResult) Merge(other *FacetResult) {
 	fr.Total += other.Total
 	fr.Missing += other.Missing
 	fr.Other += other.Other
-	if fr.Terms != nil && other.Terms != nil {
+	if other.Terms != nil {
+		if fr.Terms == nil {
+			fr.Terms = other.Terms
+			return
+		}
 		for _, term := range other.Terms.termFacets {
 			fr.Terms.Add(term)
 		}