Skip time zone warning when local and server are the same

[Smylers]

This warning is unnecessary when starting pgcli:

Using local time zone Europe/London (server uses Europe/London)
Use `set time zone <TZ>` to override, or set `use_local_timezone = False` in the config

Especially since the first line is in green, drawing attention to itself over everything else there.

It is possible to get rid of it by setting use_local_timezone = False, but I don't want to do that: if I ever happen to connect to a database which uses a different time zone, then I want to keep using local times.

Would it be possibly simply to skip displaying this when the local and server time zones are the same as each other, so there's nothing to warn about? Thanks.

[dbaty]

I agree. Here is a pull request: #1580.