sysutils/vagrant: update to 1.7.3

[mmoll]

Summary

I'll still need maintainer approval, but want to get clearance here first.
Proposed commit message:

sysutils/vagrant: update to 1.7.3

Approved by: swills (mentor), mat (mentor), Joe Benden (maintainer)

Test Plan

poudriere: http://space.kvedulv.de/FreeBSD/vagrant-1.7.3.log
portlint:

mmoll@marduk:/svn/ports/sysutils/vagrant$ portlint -ACNc
WARN: /svn/ports/sysutils/vagrant/pkg-plist: [2]: enumerating info files in the plist is deprecated in favor of adding info files into the Makefile using the INFO macro.
WARN: Makefile: [0]: possible direct use of command "install" found. use ${INSTALL_foobaa} instead.
WARN: /svn/ports/sysutils/vagrant/files/patch-vagrant-is-vagrant-installer.patch: patch was not generated using ``make makepatch''.  It is recommended to use ``make makepatch'' to ensure proper patch format.
0 fatal errors and 3 warnings found.

[swills]

Approved, but it would be nice to address some of the portlint things like INFO and using makepatch next time

[mmoll]

update to 1.7.4 in D3219