Fix deprecation messages caused by recent changes to Duration.

> I think we should actually deprecate TimeVal, and just use Duration directly instead.

Possibly. IIRC, I previously added overloads for `Duration` for where it was being used. However, I'm also of the opinion that std.socket as a whole needs a rewrite, so I'm not in a hurry to deprecate and replace small aspects of it.

> I actually think this fixes a bug, wasn't timeout.fracSec.usecs the number of microseconds less than one millisecond?

No. `FracSec` always gives you the total, not split units. The whole reason that it was created in the first place was because while it made sense to have `year`, `hour`, `second`, etc. on `SysTime`, it didn't make sense IMHO to then have `msec`, `usec`, and `hnsec` with the units split out like you have for the larger units. What you normally want is the units seconds and above split out and the sub-second units at a particular precision. So, the units seconds and above were split out, and the sub-second units - or fractional seconds - were given in an object where you could ask for the specific precision that you wanted. Maybe it should have been something where you asked for a particular number of units of precision instead (e.g. `sysTime.fracSec!3` instead of `sysTime.fracSec.msecs`), but that's the way that I did it. It made less sense with `Duration` though regardless, so it's good that it's not longer going to be on `Duration`.