fix - compatibility with vagrant 2.2.5
fix - compatibility with vagrant 2.2.5

remove the hostpath in the call to exclude_to_regexp, as this was
changed in vagrant 2.2.5 [1] and now should only be passed the pattern

note that this change is written to be back/forwards compatible and
checks the version of Vagrant to do so

[1] https://github.com/hashicorp/vagrant/commit/1b0148bc783298c7aa16a519e133bb26bcc1cc9f

smerrill/vagrant-gatling-rsync