Refer to Datastore everywhere correctly by its capitalized form

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

java/google/registry/util/CollectionUtils.java

@@ -113,7 +113,7 @@ public class CollectionUtils {
    * Turns an empty collection into a null collection.
    *
    * <p>This is unwise in the general case (nulls are bad; empties are good) but occasionally needed
-   * to cause JAXB not to emit a field, or to avoid saving something to datastore. The method name
+   * to cause JAXB not to emit a field, or to avoid saving something to Datastore. The method name
    * includes "force" to indicate that you should think twice before using it.
    */
   @Nullable

java/google/registry/util/DatastoreServiceUtils.java

@@ -18,10 +18,10 @@ import com.google.appengine.api.datastore.Key;
 import com.google.common.base.Function;
 import com.google.common.base.Optional;
 
-/** Utility methods for working with the AppEngine datastore service. */
+/** Utility methods for working with the App Engine Datastore service. */
 public class DatastoreServiceUtils {
 
-  /** Helper function that extracts the kind from a regular datastore entity key. */
+  /** Helper function that extracts the kind from a regular Datastore entity key. */
   public static final Function<Key, String> KEY_TO_KIND_FUNCTION = new Function<Key, String>() {
       @Override
       public String apply(Key key) {

java/google/registry/util/DateTimeUtils.java

@@ -33,7 +33,7 @@ public class DateTimeUtils {
    *
    * <p>This value is (2^63-1)/1000 rounded down. AppEngine stores dates as 64 bit microseconds, but
    * Java uses milliseconds, so this is the largest representable date that will survive a
-   * round-trip through the datastore.
+   * round-trip through Datastore.
    */
   public static final DateTime END_OF_TIME = new DateTime(Long.MAX_VALUE / 1000, DateTimeZone.UTC);