pihole-FTL.log is not flushed

Because a problem I saw that the pihole-FTL.log is still growing started at 2 May 2017 and not flushed.
Maybe an idea to flush this file in the same frequency of the pihole.log file to keep them synchrone

How large is it? Else than that I like this idea.

158 kB, start of the file on 2017-05-02

So I think in 1 month about 180 kB logging

This has been implemented in v3.1.