JunOS get_interfaces is reporting physical-interface MTU on logical-interfaces

[TomCos]

The logical-interface MTU is being ignored when get_interfaces returns data. Example:
`
user@device> show configuration | display set | match et-0/0/1 | match mtu

set interfaces et-0/0/1 mtu 9192
set interfaces et-0/0/1 unit 0 family inet mtu 9100
`

Python code to replicate:
junos.get_interfaces()

Incorrect results returned example:
`
et-0/0/1': {'is_up': True, 'is_enabled': True, 'description': 'interface_desc', 'last_flapped': 7251020.0, 'mac_address': 'XX:XX:XX:XX:XX:XX', 'speed': 40000.0, 'mtu': 9192},

'et-0/0/1.0': {'is_up': True, 'is_enabled': True, 'description': 'interface_desc', 'last_flapped': 7251022.0, 'mac_address': 'XX:XX:XX:XX:XX:XX', 'speed': 40000.0, 'mtu': 9192},
`

The second entry in the results is the logical interface, however as you can see, the MTU is incorrectly display 9192, as opposed to 9100.

[amylieb]

So - the problem is that junos allows you to set per-address family MTUs on the logical interfaces, eg:

set interfaces et-0/0/1 mtu 9192
set interfaces et-0/0/1 unit 0 family inet mtu 9100
set interfaces et-0/0/1 unit 0 family inet6 mtu 9000
set interfaces et-0/0/1 unit 0 family iso mtu 8000

In an instance like this, which MTU is correct? I've proposed a change that uses the smallest one, but you could easily convince me that keeping the physical mtu as the value here is better.