ReplicationIT: Do not use deprecated getRef()

Change-Id: Idf56bcb4d9e7ed514d1011f62d6738d124ba870a

src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationIT.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationIT.java b/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationIT.java
index 1e22c3f..7f68238 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationIT.java
@@ -99,7 +99,7 @@
 
   private Ref getRef(Repository repo, String branchName) {
     try {
-      return repo.getRefDatabase().getRef(branchName);
+      return repo.getRefDatabase().exactRef(branchName);
     } catch (IOException e) {
       e.printStackTrace();
       return null;