fix wrong handling of empty param in thrift/memcached transport

Author: kimchy

plugins/transport/memcached/src/main/java/org/elasticsearch/memcached/MemcachedRestRequest.java

@@ -164,8 +164,8 @@ public void setData(byte[] data) {
     @Override public String param(String key, String defaultValue) {
         String value = params.get(key);
         if (value == null) {
-            return value;
+            return defaultValue;
         }
-        return defaultValue;
+        return value;
     }
 }

plugins/transport/thrift/src/main/java/org/elasticsearch/thrift/ThriftRestRequest.java

@@ -148,8 +148,8 @@ public ThriftRestRequest(org.elasticsearch.thrift.RestRequest request) {
     @Override public String param(String key, String defaultValue) {
         String value = params.get(key);
         if (value == null) {
-            return value;
+            return defaultValue;
         }
-        return defaultValue;
+        return value;
     }
 }

plugins/transport/thrift/src/test/java/org/elasticsearch/thrift/test/SimpleThriftTests.java

@@ -76,6 +76,10 @@ public class SimpleThriftTests {
         assertThat(map.get("ok").toString(), equalTo("true"));
         assertThat(map.get("_index").toString(), equalTo("test"));
         assertThat(map.get("_type").toString(), equalTo("type1"));
+
+        request = new RestRequest(Method.GET, "/_cluster/health");
+        response = client.execute(request);
+        assertThat(response.getStatus(), equalTo(Status.OK));
     }
 
     private Map<String, Object> parseBody(RestResponse response) throws IOException {