net-mgmt/netbox: Update to 2.5.6

[kai]

Summary

• Fix whitespace in pkg-plist

Notable changes since 2.4.9:

• Modeling of patch panels and cables with introducion of new pass-through port component type
• Removed deprecated User Activity log
• Dropped support for Python 2
• Introduction of further interface types
• Implemented Select2 for select fields in forms
• Many more enhancements/bug fixes, for all changes see:

https://github.com/digitalocean/netbox/blob/v2.5.6/CHANGELOG.md

Test Plan

• poudriere (11.2, 12.0-RELEASE, 13.0-CURRENT@r342772 amd64 + i386) -> OK
• portlint -> OK
• Inplace upgrade via pkg -> OK
• Database migrations from 2.4.9 to 2.5.6 via "python3.6 manage.py migrate" -> OK
• Upgrade by using portmaster -> same issue as in PR 233442 (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233442) "FLAVOR is defined while port does not have FLAVORS"

Workrounds when using portmaster:

• uninstall/reinstall netbox
• add FLAVORS/FLAVOR hack (variant B of PR 233442) before upgrading

Adding matthew@ as subscriber because he also uses net-mgmt/netbox and to give him the possibility to test the new version.

[kai]

Removed the USE_PYTHON=noflavors . It seems bogus in that case because "distutils" are not used.

[kai]

Upstream has released 2.5.6 some hours ago which has bugfixes and some improvements.

[miwi]

LGTM