When you try to do mass update for value mappings for host and update name to existing one, name is still the same, but mappings of the existing value mapping get changed even though they shouldn't have been updated.

Steps to reproduce:

1. Create two value mappings for host with different mappings
2. From host list, check the checkbox of your host and press Mass update button
3. Go to Value mapping tab and choose update option
4. Press Add from link and choose any existing value mapping
5. Change its name so that it would coincide with the name of the other value mapping
6. Save

Expected result: Value mapping name and mappings of existing value mapping should not change
Actual result: Existing value mapping mappings are changed