util.mount_cb only supports passing through a single (positional) argument to the wrapped function

This bug was originally filed in Launchpad as [LP: #1884979](https://bugs.launchpad.net/cloud-init/+bug/1884979)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2020-06-24T14:45:54.248299+00:00

date_fix_committed = None

date_fix_released = None

id = 1884979

importance = undecided

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1884979

milestone = None

owner = oddbloke

owner_name = Dan Watkins

private = False

status = triaged

submitter = oddbloke

submitter_name = Dan Watkins

tags = []

duplicates = []

_Launchpad user **Dan Watkins(oddbloke)** wrote on 2020-06-24T14:45:54.248299+00:00_

This makes it difficult to use with a function that needs to take more than a single positional parameter, or any keyword arguments; you have to partially apply the function before calling mount_cb.

I propose adding `args` and `kwargs` parameters, which will be passed to the callback function using *args and **kwargs. (For bonus points, refactor all current callsites to pass `args` so we can drop the `data` argument entirely.)