Network: Don't group mountpoints with different schemes
We're currently accepting mountpoints from different schemes than the previously handled ones.
We incorrectly base ourselves on the device ID only, but since this is usually the hostname, it's not enough to discriminate between a service
A exposed by hostname
HOST, and a service
B also exposed by hostname
The database needs to be updated to use
scheme as a
UNIQUE value, instead of
Probing the device also needs to provide the scheme, in order to avoid considering a device as a candidate if it doesn't match the protocol we're watching.