Remove unused mocking of getObjectDatabase

On Gerrit master, the mocking of getObjectDatabase
isn't needed: unused mockings would generate test failures.

Change-Id: I37eeccc9ef289d01dad167a01e98bf01f342b7f8
diff --git a/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/SharedRefDbRepositoryTest.java b/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/SharedRefDbRepositoryTest.java
index 5bb4fb4..09d6617 100644
--- a/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/SharedRefDbRepositoryTest.java
+++ b/src/test/java/com/gerritforge/gerrit/globalrefdb/validation/SharedRefDbRepositoryTest.java
@@ -52,7 +52,6 @@
   private void setMockitoCommon() {
     doReturn(true).when(repository).isBare();
     doReturn(genericRefDb).when(repository).getRefDatabase();
-    doReturn(objectDatabase).when(repository).getObjectDatabase();
     doReturn(sharedRefDb).when(sharedRefDbRefDbFactory).create(PROJECT_NAME, genericRefDb);
   }