devel/google-styleguide: Update to 20170630, Take MAINTAINER'ship

[ultima]

Summary

• Updated to 20170630
• New maintainer Jov <[e-mail]>

PR\: 220445
Sumitted by\: Jov <[e-mail]> (maintainer)
Reviewed by\: lifanov (mentor), matthew (mentor)
Approved by\: lifanov (mentor), matthew (mentor)
Differential Revision\: https://reviews.freebsd.org/DXXXXX

Test Plan

portlint:
WARN: Makefile: for new port, make $FreeBSD$ tag in comment section empty, to make SVN happy.
0 fatal errors and 1 warning found.

poudriere:
103i386
103amd64
110i386
110amd64
12i386
12amd64

[lifanov]

Looks good for now as-is, but just a note that for new ports that don't have actual releases, we prefer versions with a "g" in them, like so: "g20170630".