Stop running services if the user wants to change provider.

**DO NOT MERGE**

If the user changes the selected provider, we ask if he wants to stop the running servers since is needed to do the change.

Right now there is a problem that when the services are stopped, the EIP widget seems to have the firewall up (has two buttons)... working on it.
It is initialized with `-1` that means 'no item selected' in the QComboBox class.