MAAS CLI bond specific parameter names are wrong for interface update help message

When using MAAS CLI, the help message for "interface update" displays wrong parameter names in the section specific to bonds.

The parameter names are shown to be separated by dashes "-", however when actually trying to update them, MAAS only seems to accept underscores "_". For example, "bond-lacp_rate" should be "bond_lacp_rate".

See below for current output of the help message.

# Output
root@maas-lxc:/home/ubuntu# maas my-maas interface update -h
...
Following are parameters specific to bonds:

:param bond-mode: The operating mode of the bond.
    (Default: active-backup).
:param bond-miimon: The link monitoring freqeuncy in milliseconds.
    (Default: 100).
:param bond-downdelay: Specifies the time, in milliseconds, to wait
    before disabling a slave after a link failure has been detected.
:param bond-updelay: Specifies the time, in milliseconds, to wait
    before enabling a slave after a link recovery has been detected.
:param bond-lacp_rate: Option specifying the rate in which we'll ask
    our link partner to transmit LACPDU packets in 802.3ad mode.
    Available options are fast or slow. (Default: slow).
:param bond-xmit_hash_policy: The transmit hash policy to use for
    slave selection in balance-xor, 802.3ad, and tlb modes.

# Version
MAAS Version 2.1.0+bzr5480-0ubuntu1 (16.04.1)