Fix relativeFetch test.

It's unclear how this ever got broken.

Change-Id: I4da6d73c216433911193afd3f4564845d0e11b64

javatests/com/googlesource/gerrit/plugins/supermanifest/RepoSuperManifestIT.java

diff --git a/javatests/com/googlesource/gerrit/plugins/supermanifest/RepoSuperManifestIT.java b/javatests/com/googlesource/gerrit/plugins/supermanifest/RepoSuperManifestIT.java
index 6c1b24c..f97451a 100644
--- a/javatests/com/googlesource/gerrit/plugins/supermanifest/RepoSuperManifestIT.java
+++ b/javatests/com/googlesource/gerrit/plugins/supermanifest/RepoSuperManifestIT.java
@@ -551,10 +551,11 @@
     assertThat(branch.file("path1").getContentType()).isEqualTo("x-git/gitlink; charset=UTF-8");
 
     Config base = new Config();
+    String gitmodule = branch.file(".gitmodules").asString();
     BlobBasedConfig cfg =
-        new BlobBasedConfig(base, branch.file(".gitmodules").asString().getBytes(UTF_8));
+        new BlobBasedConfig(base, gitmodule.getBytes(UTF_8));
 
-    String subUrl = cfg.getString("submodule", "path1", "url");
+    String subUrl = cfg.getString("submodule", testRepoKeys[0].get(), "url");
 
     // URL is valid.
     URI.create(subUrl);