Fix multi-cluster search test with two shards

Let us just hard code the test to always use one shard, it is easier
that way.

Author: jasontedor

qa/multi-cluster-search/src/test/resources/rest-api-spec/test/remote_cluster/10_basic.yml

@@ -27,6 +27,8 @@
         indices.create:
           index: field_caps_index_1
           body:
+              settings:
+                index.number_of_shards: 1
               mappings:
                 t:
                   properties:
@@ -51,6 +53,8 @@
         indices.create:
           index: field_caps_index_3
           body:
+              settings:
+                index.number_of_shards: 1
               mappings:
                 t:
                   properties: