Fix ServiceTemplate#picture= with models

When creating a service template with a Picture that already exists
(done in some of specs in other repos), the previous form of this method
would break as `create_picture` was not relevant for updating pictures
that already exist.

This fix #should™ fix that, but more relevant eyes should probably take
a look just to make sure...

app/models/service_template.rb

@@ -401,9 +401,11 @@ def provision_request(user, options = nil, request_options = {})
 
   def picture=(value)
     if value
-      super unless value.kind_of?(Hash)
-
-      super(create_picture(value))
+      if value.kind_of?(Hash)
+        super(create_picture(value))
+      else
+        super
+      end
     end
   end
 

spec/models/service_template_spec.rb

@@ -1002,6 +1002,27 @@
       expect(service_template.resource_actions.last.dialog).to eq(service_dialog)
       expect(service_template.config_info).to eq(catalog_item_options[:config_info])
     end
+
+    context "with an existing picture" do
+      let(:picture) { Picture.create(catalog_item_options.delete(:picture)) }
+
+      it "creates the picture without error" do
+        expect {
+          service_template = ServiceTemplate.create_catalog_item(catalog_item_options, user)
+          service_template.picture = picture
+        }.not_to raise_error
+      end
+
+      it "has the picture assigned properly" do
+        service_template = ServiceTemplate.create_catalog_item(catalog_item_options, user)
+        service_template.picture = picture
+        service_template.save
+
+        service_template.reload
+
+        expect(service_template.picture.id).to eq picture.id
+      end
+    end
   end
 
   describe '#update_catalog_item' do