Calendar: Issues when removing custom fields

There are a few issues when deleting a custom field in Calendar:

1. The confirmation message appears after the custom field has been removed
2. The "Save Field Changes" button should just say "Remove"
3. The "Cancel" button should be removed from the page
4. When removing a custom field, there should be a confirmation to confirm or deny the removal (like when deleting an assignment or an announcement from those respective tools)

Original Description:

· Explanation: The Instructor in the main view of the Calendar, click on the Add/Edit Fields tab. Once there, the instructor introduces a Field name to add and click on Create Field. After this, a new field is added. If you want you remove this new field, mark the checkbox and click on Save Field Changes, but, an emergent message appears to ask you to be sure to remove this field.

· Expected result: The instructor choose remove the new field and, after click on Save Field Changes, an emergent message appears to avoid you remove it without be sure. Further, when you save the changes, you should be redirected to Calendar main view.

· Obtained result: When you click on the Save button, no label is shown. Instead of this, the field is removed, and after that, the message appears. When you save the changes are not redirected to the calendar main view.