Fix protocol detection from https system property (#61) (#64)

Signed-off-by: Andriy Redko <andriy.redko@aiven.io>
(cherry picked from commit 2cfae7d)

src/integrationTest/java/org/opensearch/index/codec/rest/CreateIndexWithCodecIT.java

@@ -29,6 +29,8 @@
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 
+import java.util.Objects;
+
 import javax.net.ssl.SSLContext;
 
 import static org.opensearch.index.codec.customcodecs.CustomCodecService.ZSTD_CODEC;
@@ -100,7 +102,7 @@ protected void configureHttpOrHttpsClient(RestClientBuilder builder, Settings se
 
     @Override
     protected String getProtocol() {
-        return Strings.isNullOrEmpty(System.getProperty("https")) ? "http" : "https";
+        return Objects.equals(System.getProperty("https"), "true") ? "https" : "http";
     }
 
     /**