proto.rb in gcloud-0.3.1

- old
+ new

@@ -12,10 +12,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
 require "gcloud/proto/datastore_v1.pb"
+require "gcloud/datastore/errors"
 
 module Gcloud
   module Datastore
     # rubocop:disable all
 
@@ -61,9 +62,11 @@
           v.timestamp_microseconds_value = self.microseconds_from_time value
         elsif Gcloud::Datastore::Key === value
           v.key_value = value.to_proto
         elsif Gcloud::Datastore::Entity === value
           v.entity_value = value.to_proto
+        elsif NilClass === value
+          # The correct behavior is to not set a value property
         elsif TrueClass === value
           v.boolean_value = true
         elsif FalseClass === value
           v.boolean_value = false
         elsif Float === value