Fix a network configuration issue of Fedora [GH-1997]

Support Predictable Network Interface Names.
v1.5.2
website/www: up for deploy
kernel/v2: check if type is set before validation
core: Allow direct box adding again
core: BoxCollection#find version constraint can benil
A simple typo
Merge pull request #3384 from joanbarros/patch-1

A simple typo
Merge branch 'support_fedora_predictable_network_interface_names' of https://github.com/khiro/vagrant into fix-fedora
Fix hostname change
synced_folders/rsync: enable override of default chmod flag
fixed new file creation to follow guest's umask on Windows by default
Merge pull request #3394 from Arxisos/master

synced_folders/rsync: enable override of default chmod flag
Update version for dev
Update CHANGELOG
synced_folders/rsync: style
Merge pull request #3207 from khiro/support_fedora_predictable_network_interface_names

guests/fedora: Fix a network configuration issue of Fedora [GH-1997]
Update CHANGELOG
Merge pull request #3382 from ndemonner/fix-fedora

guests/fedora: fix hostname setting
Update CHANGELOG
website/docs: note box update checking enabled by default [GH-3391]