pixma backend config does not support mfnp protocol

Hi,

When trying to configure my scanner (Canon i-Sensys MF645Cx) I noticed that the pixma.conf configuration file only supports bjnp protocol. Even when explicitly specifying mfnp as the method bjnp is used. This is as specified in the config file, however the man page states that both are supposed to be supported.

E.g. a config line with mfnp://192.168.1.163 gives:

[bjnp] udp_command: ERROR - no data received (timeout = 10000)
[bjnp] bjnp_init_device_structure: Cannot read mac address, skipping this scanner
[bjnp] udp_command: ERROR - no data received (timeout = 10000)
[bjnp] add_scanner: ERROR - Cannot read scanner make & model: mfnp://192.168.1.163:8612/timeout=10000

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