local_address does not work when threads > 1

The newer variable, local_address, does not get set when threads > 1.

With the following configuration:

[maxscale]

threads=1

local_address=192.168.1.183

log_info=1

Then in the maxscale.log, I see an entry like:

2018-03-02 13:43:05   info  : Bound connecting socket to "192.168.1.183".

When I increase threads to be > 1:

threads=2

local_address=192.168.1.183

log_info=1

Then there is no such message in the log.

And it is more than not being logged, it is not set at all, afaict, because we see errors like this (it is using the wrong IP address, and not the one specified by "local_address"):

[Warning] Access denied for user 'maxscale1'@'192.168.1.184' (using password: YES)