Test: don't use 0 size for terms aggregation

It is no longer allowed.

core/src/test/java/org/elasticsearch/search/aggregations/bucket/BooleanTermsIT.java

@@ -156,7 +156,7 @@ public class BooleanTermsIT extends ESIntegTestCase {
         SearchResponse response = client().prepareSearch("idx_unmapped").setTypes("type")
                 .addAggregation(terms("terms")
                         .field(SINGLE_VALUED_FIELD_NAME)
-                        .size(randomInt(5))
+                        .size(between(1, 5))
                         .collectMode(randomFrom(SubAggCollectionMode.values())))
                 .execute().actionGet();