Refer to Datastore everywhere correctly by its capitalized form

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=147479683

javatests/google/registry/tools/CommandTestCase.java

@@ -83,7 +83,7 @@ public abstract class CommandTestCase<C extends Command> {
       jcommander.parse(args);
       command.run();
     } finally {
-      // Clear the session cache so that subsequent reads for verification purposes hit datastore.
+      // Clear the session cache so that subsequent reads for verification purposes hit Datastore.
       // This primarily matters for AutoTimestamp fields, which otherwise won't have updated values.
       ofy().clearSessionCache();
       // Reset back to UNITTEST environment.