CreateChangeUsingMultiGerrit: Set test access modifier

Based on not being reused yet by other aggregating scenarios; private.

Change-Id: I4cbe351aa1f98cb6b1c86a4df2e89884efa72266

src/test/scala/com/googlesource/gerrit/plugins/multisite/scenarios/CreateChangeUsingMultiGerrit.scala

diff --git a/src/test/scala/com/googlesource/gerrit/plugins/multisite/scenarios/CreateChangeUsingMultiGerrit.scala b/src/test/scala/com/googlesource/gerrit/plugins/multisite/scenarios/CreateChangeUsingMultiGerrit.scala
index 6e3dcd8..8fcddd4 100644
--- a/src/test/scala/com/googlesource/gerrit/plugins/multisite/scenarios/CreateChangeUsingMultiGerrit.scala
+++ b/src/test/scala/com/googlesource/gerrit/plugins/multisite/scenarios/CreateChangeUsingMultiGerrit.scala
@@ -29,7 +29,7 @@
 
   override def relativeRuntimeWeight = 10
 
-  val test: ScenarioBuilder = scenario(unique)
+  private val test: ScenarioBuilder = scenario(unique)
     .feed(data)
     .exec(httpRequest
       .body(ElFileBody(body)).asJson