Don't queue EmsRefresh if using streaming refresh

If a target's ems is using streaming refresh don't queue an EmsRefresh
because it will not be processed.

app/models/ems_refresh.rb

@@ -51,6 +51,9 @@ def self.queue_refresh(target, id = nil, opts = {})
       h[e] << t unless e.nil?
     end
 
+    # Drop targets on EMSs which are using streaming refresh
+    targets_by_ems.reject! { |ems, _| ems.streaming_refresh_enabled? }
+
     # Queue the refreshes
     task_ids = targets_by_ems.collect do |ems, ts|
       ts = ts.collect { |t| [t.class.to_s, t.id] }.uniq

app/models/ext_management_system.rb

@@ -270,6 +270,14 @@ def self.provision_workflow_class
     self::ProvisionWorkflow
   end
 
+  def self.streaming_refresh_enabled?
+    false
+  end
+
+  def streaming_refresh_enabled?
+    self.class.streaming_refresh_enabled?
+  end
+
   # UI methods for determining availability of fields
   def supports_port?
     false

spec/models/ems_refresh_spec.rb

@@ -43,6 +43,14 @@
       target2 = FactoryGirl.create(:vm_vmware, :ext_management_system => @ems)
       queue_refresh_and_assert_queue_item(target2, [target, target2])
     end
+
+    it "with streaming refresh enabled doesn't queue a refresh" do
+      allow(@ems).to receive(:streaming_refresh_enabled?).and_return(true)
+      target = @ems
+
+      described_class.queue_refresh(target)
+      expect(MiqQueue.count).to eq(0)
+    end
   end
 
   context "stopping targets unbounded growth" do