test: fix HttpRpcContextTest to not attempt environment credentials resolution (googleapis#2876)

Author: BenWhitehead

google-cloud-storage/src/test/java/com/google/cloud/storage/spi/v1/HttpRpcContextTest.java

@@ -21,6 +21,7 @@
 import static org.junit.Assert.assertTrue;
 
 import com.google.api.client.testing.http.MockLowLevelHttpResponse;
+import com.google.cloud.NoCredentials;
 import com.google.cloud.TransportOptions;
 import com.google.cloud.Tuple;
 import com.google.cloud.WriteChannel;
@@ -66,6 +67,8 @@ public void testInvocationIdIsPassedThrough() {
     Storage service =
         StorageOptions.getDefaultInstance()
             .toBuilder()
+            .setProjectId("test-project")
+            .setCredentials(NoCredentials.getInstance())
             .setTransportOptions(transportOptions)
             .build()
             .getService();