This change adjusts a few instances of `--config-file=foo` to
`--config-file foo` (no `=`) in order to make neutron command
lines more consistent and easier to match in sudoers/rootwrap
filters.
This is particularly useful for oslo.privsep, which needs to start a
helper command with the same `--config-file` arguments (see
Ia9675dff9232e0e987a836ecaf9e842eb5c3cb18).
Change-Id: I91fe18f66f3c3bc2ccd1ca8be91be2915ed3e3ec